The city of the Thains comes under attack by a race of Kleptons in their flying machines. They fly over the city, sucking up the Thains into their craft. The Thains are unable to defend themselves since they have no weapons. The Kleptons plan is to enslave the Thains.

Two children, John and Gillian pay a visit to their grandfather who they have never seen before. When they find his house number (16) there is only a police box in a yard. The box is much bigger on the inside and he tells them that it contains a time machine. The Doctor tells John that he must not press one of the switches, but of course John presses it immediately. The police box spins rapidly and vanishes. The Doctor tells his grandchildren that they are on their way to the 29th century.

As they step out they find that the Kleptons are attacking the Thain city and Gillian is captured. John saves his sister by picking up a brick and throwing it at the Klepton ship. It drops Gillian safely but then plunges to the ground and explodes, killing the pilot who seems to be the Klepton leader. The other flying machines retreat to their base.

The leader of the Thains, Valda, tells the Doctor about the Kleptons' plan and adds that large creepers have been growing quickly all over the city and destroying the buildings. The Doctor persuades them to give up their peaceful ways and arm themselves with weapons from the museum.

When the Kleptons return John and the Thains drive off the Kleptons with heat guns. The Doctor examines a downed Klepton flying machine, to see whether it can be used against the Kleptons, but the enemy return and John is seized by one of the creepers. The Doctor uses a heat gun to save him and then starts to repair the crashed machine.

A Klepton messenger appears and demands that they surrender or the Thain city will be destroyed. The Doctor, John and Gillian climb into the flying machine and take off, narrowly avoiding a building that is being pulled down by a creeper. They set off to chase the Klepton messenger but they soon lose him. The Kleptons detect the flying craft from their fortress under the sea and drag it down with a magnetic beam.

An airlock door opens and the craft is pulled inside. The Doctor, John and Gillian are taken prisoner and led before Klepton One who explains that the Klepton planet has moved closer to its sun. The Kleptons have escaped to build an underwater city but they need Thain slaves to work the reactor in order to provide energy for both the city and the war machines. The Doctor and the children are locked up but John still has a heat gun on him. They use it to burn out of the cell, overcome the guards and make their way to the reactor. The Thain slaves conceal them from the Kleptons and later they begin to plan how they will overcome the invaders.

The Doctor takes a small group of Thains into the city where they find a laboratory where the creepers are made. The Kleptons discover them and Kleptons open fire. This damages a wheel on the side of the tank holding a creeper. It breaks through the glass wall. The Doctor realises that this wheel controls the creepers so he uses it to make the creepers attack the Kleptons and the reactor.

The Doctor, John and Gillian lead the slaves back to the airlock and use the Klepton flying machines to escape from the fortress. It promptly explodes. In the Thain city, Valda asks them to stay but the Doctor is wants to return to the police box and try to take John and Gillian home.

A fault develops in the controls of the TARDIS, and Dr Who tells John and Gillian that as a result the time and space machine will materialise prematurely. Above the surface of a barren asteroid, a rock hurtling through space collides with the spinning TARDIS, sending the craft plummeting down. The TARDIS smashes into the surface of the asteroid, damaging the controls, and Dr Who fears that they could be marooned there permanently. They discover, on leaving the TARDIS, that the asteroid has low gravity, and also that they may not be alone, since a small rocket ship has come to rest some distance away. The three are making their way towards it when a large, scaly creature reminiscent of a dinosaur comes into view and bears down on them. The gravity level, however, allows them to make a big leap towards the rocket, which they now perceive to be damaged as well, most likely from a similar crash landing to their own. They climb in through its hatch before the creature is able to get there. Relief is short-lived, though, since a diminutive, humanoid astronaut with a bald head and large eyes flourishes a tubular ray gun and threatens to reduce them to atoms.

Dr Who calms him down, explains that they too have crashed in this wild place, and suggests that they work together to achieve their respective escapes. The astronaut tells them that his name is Grig, and reveals that he is from the planet Theros, where a mysterious disease has broken out and is gradually weakening most of their race. Grig, one of those unaffected, had set off into space at the request of the President in the hope of discovering a planet where an antidote was known, but his ship was forced down onto the asteroid after encountering a storm of meteorites. The craft’s systems were affected, and he is therefore stranded. He asks if they might all escape in the old man’s ship, but the Doctor discloses that the controls of the TARDIS are damaged too. The reptile outside attacks the rocket, shaking it and battering its hull still further, so Dr Who sets about fixing the instruments in the hope of lifting off before the creature wrecks the craft. Just as destruction seems inevitable, Dr Who completes his work and the ship blasts off, escaping both asteroid and monster. Unfortunately, the TARDIS has been left behind as well. The Doctor and his grandchildren, resolved to help the Therovians if they can, now head for Theros with Grig.

They find that the situation has worsened, and that the President himself is now very ill. There is one glimmer of hope though: the oldest and wisest member of the Therovian race, Wopan, has learned that a certain moss, to be found only on a planet called Ixon, may provide the antidote they need. Dr Who, John, Gillian and Grig leave forthwith on their new quest. After many weary days of space travel, Grig’s ship touches down on Ixon, a bleak and forbidding wasteland of ice. As they open the hatch to leave the craft, they find a group of flint-eyed, sharp featured warriors awaiting them, one of whom informs them that strangers are not welcome, and that they are to be taken to the Great Ixa for questioning.

Dr Who points out to his group that they are outnumbered and have no choice but to comply, and that in any case it might be as well to put the Therovians’ plight to the ruler of this planet and ask for help in locating the moss. With the grim soldiers, they board an open-topped metal car and are soon skimming across the hard-packed ice. The vehicle enters a large cavern hung with sumptuous drapes. On a high-placed throne sits a truly forbidding figure, robed and crowned. Dr Who explains the situation that has led to their visit to Ixon, and surprisingly the Great Ixa agrees to the moss being collected, so perhaps appearances are deceptive. Ixa informs them that the moss grows only in a network of underground caves connected by tunnels, and that the travellers must gather it themselves, since the Ixons have always been superstitious about these particular tunnels and few have ever ventured into them. One of the metal cars and some warmer clothing are provided for the use of the visitors, though, together with directions to a particular cave mouth and the tunnels. Clad in their borrowed furs, Dr Who and his party set off in their transport. The Great Ixa watches them go with a mirthless smile. He has another, hidden agenda.

Some way into the tunnels, the track that the travellers have been following ends and they are obliged to finish the journey on foot. Dr Who remarks that the temperature has not risen at all – Ixon must be a solid ball of ice. Passing into a large cavern with a yawning crevasse across it, they see the exuberant moss growing all along one of the pitted walls and begin to gather as much of it as they can carry back to their vehicle between them. The Doctor suddenly notices a long-horned bison-like creature that has entered the cavern and is watching them intently, prior to making its charge. Grig proves surprisingly wiry for such a small being. Having seized the animal by the horns, he single-handedly pitches it into the crevasse. The four make for the ice car, each with an armful of moss. On their return a group of Ixon guards are waiting and conduct them back to Ixa’s throne. The Great Ixa laughs scornfully at their foolishness. Now they have collected the moss, he intends that the Therovians should pay for it with all their wealth.

Dr Who denounces Ixa as a treacherous villain, strikes a handful of his everlasting matches and sets fire to the drapes looped across the cavern wall. The heat throws up a thick cloud of smoke from the ice, which enables the Doctor and his companions to evade the guards, commandeer an ice carriage and head for Grig’s spaceship. The Ixons open fire as the travellers climb aboard carrying the moss, but Grig succeeds in lifting off before his craft is damaged. Many days later they arrive back on Theros, where scientists set about extracting the antidote from the moss. The resultant liquid restores the Therovians. Grig returns Dr Who and his grandchildren to the asteroid where they left the TARDIS, and after the Doctor has effected repairs to his craft and farewells have been made Grig watches as the machine whirls away into space.

---

Reprinted in Doctor Who Classic Comics #12

2075: a supply ship leaves Earth on its way to Venus. It promptly disappears, the latest in a long line to do so.

The TARDIS materialises in a cloud of mist and the scanners reveal that they are on top of a space station. The Doctor and his grandchildren see the crew being led off the supply ship by armed men. John drops a heavy weight onto one of the guards and knocks him out. The Doctor finds the crews of the other missing ships and talks to them. They inform him that the station is being run by Captain Anastas Thrax and his pirates. These villains catch supply ships and sell their cargo to other planets. However, Thrax arrives armed with a gun and catches the Doctor and his grandchildren.

After they are locked in a cell Thrax returns to his control room and offers to sell Venus some supplies for the exorbitant price of ten thousand Earth pounds. The desperate Venusians are forced to agree. John uses a bar of soap to make the steps of the prison slippery. When a guard enters and falls down the steps the prisoners escape. The Doctor sends one crew off in the supply ship to warn Earth about Thrax's scheme. The others have to stay behind to tell the rescuers where the station is as no-one could find it again in the mist. Unfortunately, the guards return and the prisoners are trapped. Fortunately, they are trapped next to bags of potatoes and so they throw the vegetables at the guards and overcome them.

The Doctor orders Thrax to show him how the mist is made. At the top of the station they find the machines that make the cloud. The prisoners smash the machines with more potatoes. The mist disperses and the Earth police arrest Thrax and the pirates. The Doctor and his grandchildren return to the TARDIS and set off on their travels again.

On the lunar-like planet Vortis, the TARDIS lands beside a huge boulder and near an enormous crater. Dr Who announces to his grandchildren, John and Gillian, that he has visited this world before, when he helped to defeat the giant ants called Zarbi. No sooner have the three left the TARDIS than they see two of the creatures – and to the Doctor’s amazement they are flying! He has barely commented to John and Gillian about this when the Zarbi demonstrate another new feature: a sting weapon powerful enough to blast a rock to pieces.

The butterfly-like Menoptera, the Doctor’s allies in his previous struggle, arrive on the scene. Generations have passed, but the Doctor’s name is still remembered. The Menoptera describe how the Zarbi, after their brain (a reference to the Animus of the television story) was killed, worked with them to till the soil and make Vortis habitable again. Then new problems arose: the Zarbi became rebellious once more and unaccountably developed the power of flight.

The Doctor accompanies the Menoptera to the hills, where Zarbi activity is centred. On the way they come across a deserted alien spacecraft and realise that there must be other beings on the planet. Moving on, they reach the Zarbi base: a mushroom-shaped metal tower encircled at some distance by a deep trench. John picks up a rock that is shot with veins of what Dr Who identifies as Galvinium X, a very rare and valuable mineral with powerful qualities. If the Zarbi made weapons with it the armaments could be terrifying.

A non-flying Zarbi appears and menaces Gillian. They manage to overpower it, but a huge group of the creatures is approaching. The Doctor notices a pile of mined Galvinium X near the edge of the trench. While the Menoptera swoop into the air and distract the attention of the Zarbi, Dr Who edges nearer to the mineral and uses a Menoptera weapon to ignite it. There is a huge explosion that scatters the Zarbi. Triumph, however, is short-lived: the flying Zarbi now swoop down to attack. One is shot down, but another seizes the Doctor and flies off with him.

A Menoptera follows and watches as the old man is taken into the mushroom tower via a roof hatch, then returns to John and Gillian with the news. John’s attention is then caught by the flying Zarbi that was shot: a spindly hand is emerging from a hole in its underside. The flying Zarbi are fakes, flown by the alien Skirkons, one of whom now comes fully into view: a skinny creature with a face reminiscent of an owl’s.

John and Gillian, upon whom everything now seems to depend, squeeze inside the abandoned Zarbi shell and succeed in piloting it to the mushroom tower and in through the roof hatch. Leaving their camouflage, they locate the Skirkon control room, where the Doctor is secured to a metal bench. A laser beam is moving inexorably towards him.

The children free their grandfather, but are spotted by the Skirkon leader, Zarka, who is forcing captured Menoptera to quarry Galvinium X. Dr Who has noticed a small machine topped with a transparent dome, and believes it to be a contrivance with which Zarka controls the real Zarbi. Before he can be prevented, the Doctor hurries to the machine and deactivates it, releasing the creatures from the device’s power. 

The time travellers escape in two of the flying Zarbi outfits, but Zarka warns via a loudspeaker that he still has the whip hand and has given orders that the humans, and every one of the Menoptera, are to be ruthlessly mown down. The flying Zarbi begin to leave the tower to carry out the instructions, but the Doctor turns his own Zarbi disguise back towards the Skirkon base and operates its sting gun, aiming for piles of Galvinium X which are very close to the tower. They all explode more or less together, taking the mushroom tower and the Skirkons with them and creating a spectacular conflagration.

Later, the Menoptera bid farewell to Dr Who and his grandchildren beside the TARDIS. Soon afterwards there is a sudden rush of wind and the time and space machine disappears.

The TARDIS swirls through space until it arrives on an Earth-like planet. Convinced that it is Earth, Gillian rushes out and is promptly captured by a robotic sphere that flies away with her. More spheres arrive and the Doctor and John are forced back into the TARDIS. The Doctor electrifies the TARDIS exterior to hold the spheres off but the spheres cut through the raised roadway that the TARDIS has landed on. The TARDIS falls through to the ground below. The spheres repair the road above their heads.

The Doctor and John see a group of men in some bushes nearby and the Doctor quickly learns how to talk to them. One of the men explains that planet has one side always facing the sun. this side is uninhabitable because it is so hot, as is the other side which is a frozen wasteland. There is a narrow strip between which is the only part of the planet that is fertile. This strip is the domain of the robots: the Gyros. The Gyros prevent humans from entering this zone. The Doctor asks the men to help him to rescue Gillian. They make their way to the Gyro base but the robots are ready for them.

The Doctor sees that the Gyros weakness is their single eye and breaks one of them. John and one of the other men do the same. The Gyros turn to leave so the Doctor, John and one of the men jump on top of them and ride along the road. The man tells how his ancestors made the Gyros long ago until a disease killed thousands of his people. The Gyros took over and a few surviving people fled to the countryside. They have survived but they still have the disease: fortunately it is no longer fatal. They reach the Gyros' city and the Doctor, John and their friend hide in a food storage area. The Doctor is puzzled about the food; who is it for?

The Gyros recapture them but as they are being taken away the Doctor sees that most of the food is being mashed whilst some is washed and then cooked before being taken up a chute into a large building. The three prisoners escape from the Gyros and slide down a chute. They follow the food into the large building where they find a group of old men who have been hiding there since the disease struck. The Gyros have been used to keep the ill people out of the fertile zone. The Doctor says the illness is easy to cure with 'a simple injection'. He offers to do this if Gillian is returned to him.

One of the old men tells him that it is too late to save her, she has been taken to the Valley of Flames to be burned to death. The Doctor demands a hover car and races to the Valley of Flames. They arrive as Gillian, trapped in a capsule, is tipped down a slope and into the flames. The Doctor uses the car to bounce her to safety across the valley. They return to the TARDIS and leave.

Note: despite telling the survivors of the disease that he can cure them with an injection, there is no sign that the Doctor does so.

The story of the Pied Piper of Hamelin is retold: the town is overrun with rats; the mayor promises to pay the Pied Piper one thousand gilders to get rid of them; after the rats are gone the mayor only pays fifty gilders; the Piper steals away the children of the town and imprisons them in a wonderland of toffee apple trees and lemonade fountains; the children start to miss their parents but cannot escape. This is when the TARDIS lands and the Doctor decides to visit the Piper in his black castle.

The Doctor stuffs a haversack with a lot of equipment and, with John and Gillian, sets off to the castle. They are attacked by a dragon, but the Doctor puts out its fire a fire extinguisher from his haversack. Next they are trapped in a bog covered with an impenetrable black mist. A mysterious light leads them further into the bog and then disappears: they are stranded. The Doctor produces an echo-sounder to see how deep the water is and leads them to safety.

They eventually reach the castle after a hearty breakfast from the haversack's depths. The Piper lets them in to the courtyard but he will not let the children go unless the Doctor can pass three tests.

The first teat is to catch him: he promptly turns invisible but the Doctor takes out a radar and they chase the Piper down. The next test involves following the piper out of a high window and floating down to the ground. Fortunately, the Doctor has a parachute.

Finally, the Piper starts to play a tune on his pipe which the Doctor must copy note for note. Despite apparently not listening and rummaging around in his haversack instead, the Doctor manages to play the exact same tune. It transpires that he packed a tape recorder and was merely miming to the tune he recorded.

The Piper frees the children and the Doctor leads them children back to the town. He demands that the Mayor pays the full fee of one thousand gilders and returns to the castle but the Piper's wonderland has vanished. The Doctor leaves the money in a cave, saying that nobody can tell what these magical sorts will do next. They return to the TARDIS and leave.

Monday, 20 July 1970, and the first men are set to land on the moon. The two astronauts, Colonel Roberts and Major Simms, make a safe landing and disembark from their capsule. They look across the moon's surface and are astonished to see a blue police box. They walk across to investigate, but the moon's crust cracks beneath them and they plunge into a chasm. The Doctor says that they must go out to help. Gillian points out that there is no air on the moon but the Doctor has a solution: small breathing devices. The Doctor also takes a blackboard and chalk.

Standing at the top of the chasm, the Doctor writes a message to the astronauts reminding them that the moon's gravity is only one sixth of that on Earth so they can simply jump back out. He then returns to the TARDIS with the astronauts to explain that as far as history is concerned he was never there and their place as first men on the moon is secure.

The video scanner in the TARDIS seems to have malfunctioned so the Doctor opens the door to see where they have landed. They are perched on a rock in the middle of the sea and a large wave washes the Doctor and his grandchildren away from the TARDIS. To their surprise a small boat rises up from the sea underneath them. Although they are safe for a while they notice that the boat is badly damaged and in danger of sinking. Suddenly, there is an explosion at the front of the boat which, magically it seems, is now repaired. Motoring backwards across the sea the boat comes to a beach where some men pull it onto the sand. The men start to speak but their words come out backwards and Gillian explains that everything is happening back to front.

The men hide them in a cart in which they go to a wood. While they are hiding there the Doctor comes to the conclusion that the TARDIS must be to blame. Somehow it has started them running backwards in time. They see some soldiers talking about prisoners escaping from a camp. The Doctor decides that they must go to this camp. When they get there they see a window with some broken bars so the Doctor gets his grandchildren to climb up into a cell and then follow them in.

The Doctor repairs the bars. A soldier leads them out to the Captain of the guard and from there they are taken to the top of a cliff. They see that they are close to a rocket launch station, which is obviously top secret. The TARDIS rises up out of the sea, standing on a piece of the cliff that reattaches itself to the cliff. The Doctor tells the children that they must have stepped out of the TARDIS just moments before it fell into the sea. The three of them get back into the TARDIS, thus completing the whole story in reverse, and they set off on their journeys again.

The TARDIS lands on what seems to be a barren, rocky world. As soon as the three travellers step out a large green hand reaches down and snatches the TARDIS. The trio start to climb up a cliff in pursuit but another hand, attached to a giant lizard, reaches down and takes the Doctor. John and Gillian climb on and reach the top. They see the Doctor talking to his captor. He says that it is friendly. One after another the children are also picked up by the lizard and placed beside the Doctor on a rocky pinnacle from which escape is impossible. The lizard leaves.

After sleeping the night away they wake up to find the lizard, and three others, peering at them. The other three lizards leave and the Doctor uses his watch to hypnotise the remaining lizard. After it is asleep they climb down its rough back to safety. The other three lizards see them and give chase. The only escape is into a cave, but no sooner are they inside than the lizards use boulders to block the cave mouth. John notices the cave is still light so there must be another way out. They follow the light and find the other exit. Beside it is the TARDIOS and another lizard. They make it inside the TARDIS and leave the planet.

Sinister robots on the planet Bellus are engaged in a war with their neighbouring planet, Demeter. The people of Demeter are rallying to defend themselves against the next assault when the TARDIS arrives. The Doctor leads his grandchildren through the strangely deserted city until they round a corner and find themselves face to face with a large group of people armed with a destructor weapon.

The Doctor produces a badge in the shape of a star that convinces the emperor of Demeter that he is their friend. The emperor orders a feast of welcome. Before they can eat there is an earth tremor. The dreaded attack by the robots of Bellus has started.

As the city starts to crumble the Doctor tells the emperor to get the people out of the buildings and onto the water so that they will be safe from the earth tremors won't reach them. He realises that he can protect them all if he can get back to the TARDIS to activate the tremulator. The Doctor and John race through the streets as buildings fall apart around them. The Doctor loses his way but John guides him to the TARDIS and they run inside just as a tower collapses on top of them. The Doctor activates his tremulator but then realises that he has lost Gillian in the confusion.

Fortunately he sees Gillian, with the Emperor, on the video screen. He sends up a signal rocket to tell the people that they are safe and can return to the city. Once the emperor returns the Doctor can explains that his tremulator not only protected Demeter but boomeranged the shock waves back to Bellus. This destroys the robots' planet. Gillian is given a large jewel as a thankyou gift.

The TARDIS arrives on the planet Go-Ray. As the children step out, Gillian spots a tortoise-type creature that suddenly speeds away from her at an extraordinary rate. The Doctor tells John and Gillian that Cardium was discovered on Go-Ray and as a result everything has a large amount of energy. This means that the children and the Doctor can float above the ground. They soon meet the Go-Rays. These are metal creatures that balance on top of a single wheel. The Go-Rays seem scared of meeting people with legs and race away.

The Doctor leads his grandchildren into the local city to Cardium HQ to meet with the Go-Ray leaders. Unfortunately, as they arrive the Cardium reactor fails. The travellers are accused of being spies and find themselves in prison. Fortunately, the prison was built for creatures with wheels and the four-limbed prisoners find it easy to climb up to a skylight and escape. The Doctor fashions some wooden skis so that they won't leave footprints for the Go-Rays to follow. They get back to the TARDIS but the Doctor heads past it into a cave where there are pools of mercury which they can use to replace the Cardium. This will repair the reactor and clear them of accusations of spying. As they leave the cave the Go-Rays are waiting for them.

The Doctor asks John for his bag of marbles and scatters them across the floor so that the Go-Rays are unable to balance. They run back to Cardium HQ and put on protective suits to hide their legs. They make their way past the guards into the reactor. Their legs are spotted by the guards as they add the mercury to the machine. The Go-Rays seal the door with the travellers trapped inside.

The Doctor puts the mercury into the reactor, preventing a major disaster. The doors are opened and the Go-Ray leader accuses them of spying again. The Doctor denies this, saying that he is a powerful magician who has saved the day. To prove his magical powers he uses a concealed magnet to make the Go-Ray sway from side to side. Convinced of the Doctor's power - and benevolence - the leader lets them leave.

After landing on a barren and rocky planet the Doctor sets out to explore with his grandchildren. To their dismay, the TARDIS sinks through some sand and disappears. The Doctor suggests that it may have fallen through to a cave. They find a cave mouth with some steps leading down to a very strange sea. It casts no reflections and has so much oxygen that they should be able to breathe underwater. The Doctor has also brought flippers for all three of them in case such a thing should arise. John is caught by a giant crab but the Doctor drives it off with an electroliser. No sooner have they escaped than they fall out from the bottom of the water onto dry land.

In a cave they find the TARDIS being tied up by small talking frogs. The frogs want to use the TARDIS as bait to catch a large shark that has been eating them. The Doctor agrees to help and the TARDIS attracts the giant shark into a net where it is pulled down out of the water. Now the shark is dead the frogs can eat it as opposed to the other way round, as the Doctor gleefully points out. John and Gillian are given a treat by the frogs: a ride on a giant sea-horse. John is attacked by a giant octopus but the Doctor saves him by producing a feather and tickling the octopus. No sooner is this panic over than they discover that the TARDIS has vanished once more.

Gillian is pulled down into a cave. The Doctor and John make their way down and find Gillian, the TARDIS and the Ancient Mariner. This old sea-faring gent is planning to live in the TARDIS after his vanished. The Doctor manages to find some materials to knock up a small house for the mariner who is extremely grateful. They regain the TARDIS and continue on their journey.

After the TARDIS lands on a snow-covered planet, the Doctor and his grandchildren encounter Santa Claus. He tells them that he has moved to the planet from the North Pole because of all the noisy aeroplanes that pass over his former home. Not that his new home is much better; there is the Demon Magician who continually bothers him and, as a result, Santa has fallen behind in his toy production.

The Doctor lets him use his instant modeler (which he calls his 'magic box'). This makes models out of real objects. He leaves John and Gillian helping Santa while he goes off to make a lot of TARDIS models - the in-demand toy this Christmas. When the others seek him out to collect the models he is missing. All they find are some mysterious footprints.

When they find him, the Doctor is being menaced by a Polar Bear. He tells John to use the 'magic box' to shrink the bear which soon runs away. They return to the TARDIS to leave but the Demon Magician has placed a huge wall in their way.

They use the 'magic box' to make a squirrel big enough for them to ride over the wall. At the TARDIS is a note from Santa. He has already left to deliver the TARDIS models. The Doctor still wants to prevent the Demon Magician's interference in Santa's affairs but the Magician creates a living snowman which attempts to kill John and Gillian.

The Doctor's box fires heat rays to melt the snowman. The Demon Magician hides in a giant snowball that rolling down a mountainside to crush them. The Doctor shrinks the snowball until it fits inside a rocket from Santa's workshop. He launches the toy rocket and rids Santa of the Magician for good.

The TARDIS lands on the planet Animalia beside a zoo entrance. The Doctor, John and Gillian find the curator who gives them a tour of his premises. They reach the cage of the Didus bird, a creature that the Doctor thought was extinct, but they are horrified to find the cage empty. The Doctor and his grandchildren volunteer to find the bird but the curator warns them to beware of a savage tribe living in the nearby jungle.

They use a trail of food to lure the bird into a cage when they are attacked by the tribe. Spears are thrown and hit the nearby trees and John is taken prisoner by the tribesmen. They announce their plan to put him on a fire. The Doctor approaches them and tries to reason with them but they tell him that the Didus is a lucky omen. They decide to put the Doctor on the fire, too. He throws some magnesium onto the fire and its bright flash scares the tribe away. The travellers escape back to the jungle and make a carving of the bird from some wood.

The tribesmen take the wooden bird and let the real Didus go. The Doctor spots the Didus by a river and the travellers lure it into a cage, only for a crocodile to arrive on the scene. By the time the Doctor has used his magnesium to drive off the crocodile the Didus has gone again. When Gillian corners the Didus she is attacked by a snake but the Doctor throws his jacket over it. the Didus is frightened of the snake and runs into the cage for safety. They take it back to the zoo. The curator is doubly delighted because a space ship has also delivered a pterodactyl which completes his collection. The travellers celebrate and depart.

Rebel soldiers have invaded and taken over Space Station Z-7 as the first part of their plan to dominate the universe. They uses magnetic space mines to protect the station from a counter-invasion but the TARDIS materialises on the station and the rebels are perplexed about how they evaded the mines. The Doctor is interrogated by the rebel leader who wants to know how the defences were bypassed. He also considers the Doctor clever enough to help him complete the construction of a doomsday machine. The Doctor refuses and is taken off to a truth machine to get the information out of him.

John and Gillian are placed in a prison cell but escape into a ventilator shaft. When the guards notice they have gone the shaft is flooded. The two children climb above the water and locate the Doctor. They rescue him from the truth machine and then find a radio transmitter. The Doctor calls for help on the radio but they are immediately threatened by a flame-thrower mounted on an armoured vehicle. The Doctor floods the chamber with water. This not only puts out the flames but brings down a gantry. This is blocking their route to the controls for the mines but they find a large metal dish-shaped that they can use as a make-shift boat to reach the controls.

Once there they re-use the insulating dish to cover the aerial that sends the control signal to the mines. This allows the rescue party to approach the station. As they do, the rebels escape in their own ship, along with their doomsday weapon. As the rebels launch their ship the Doctor uses a gun to shoot the dish off the aerial. The mines are reactivated and the rebel ship is destroyed before it can get away.

In the year 2066 the TARDIS arrives on Trodos, home to the Trods, a race of robots. The travellers are taken to Super Trod who tells them that the Trods were treated as slaves by the humans on the planet. The Trods rose up and now the humans are the slaves. They are led to a prison, escape almost at once and are recaptured. Now they will be punished for their insubordination.

The Doctor uses his torch to burn through the lock and they escape again, only to fall into a lift shaft with an elevator descending to crush them. They climb onto the lift's counterweights and are taken lifted up to a door. They begin to search for the main control room so that they can immobilize the Trods. They manage to disable one robot by breaking its antenna but this warns all of the other robots. The travellers try to hide but accidentally step onto a conveyor belt that one of the Trods switches on, carrying them towards a set of rotating blades. The Doctor borrows John's penknife and cuts the conveyor belt so that they can escape.

They dodge past a group of Trods and finally make it to the control room. Sneaking in, they try to immobilize the Trods by using the switches on a control panel but they are spotted by Super Trod. The Doctor grabs Super Trod's cable and pulls it out. Super Trod explodes. The Doctor is now able to switch off the power supply to the other Trods.

The travellers now search the nearby rooms and find a dying man. His name is MacTaggart. He tells them that he was the inventor of the Trods and he created them to help him rule the human civilization on the planet. The Trods rebelled against him. When the man dies the Doctor considers that justice has been served. The travellers free the human slaves before returning to the TARDIS.

Note: unusually for this strip, the enemy would be back in a subsequent adventure - Return of the Trods.

The Doctor, John and Gillian land near to a ruined city, Gemino City. The planet of Gemino has been severely damaged after a war with the neighbouring planet of Gemina. There appear to be no survivors in the city but some of the defences are automatic and still operational. The Doctor disarms a gun so that they may pass through to look into a nearby house where they discover a dog.

Avoiding a landmine, they follow the dog to a rope bridge outside the city which collapses as John tries to cross it. The Doctor saves him and the travellers follow the dog to a house where a man, the dog's owner, is still living. He tells them that the survivors have left the city. He also tells them about the Vault of Plenty which holds essential supplies as well as other information that would be useful. Many people have tried to get into the vault but it is defended by the Guardian Dragon. Now the survivors are starving.

Naturally, the Doctor offers his assistance and takes John and Gillian with him to the Vault. They find a chamber covered with letters of the alphabet and containing a large crab-like monster. The monster will kill them unless they can tell it the first clue in the secret of Gemino. The Doctor guesses that the first clue 'G'. this allows them access to the second test: a pit of flames. On the platform above the fire they are asked for the total of the secret of Gemino. The Doctor works out that Gemino has six letters so gives the answer as six.

The next test is in a chamber of knives. They have to work out what the difference is between Gemino and their enemy Gemina. The Doctor suggests that the difference is the last letter so says 'Last'. In the next chamber is the dragon. It sets them the puzzle of the secret of Gemino, which is six numbers. Failure will result in death. The Doctor works out that each of the six numbers he is given matches up to the six letters in Gemino. The Vault of Plenty opens. The survivors now have access to their supplies.

The TARDIS lands on a planet that the Doctor has feared he will one day visit: the Haunted Planet. He is not sure that he believes in the legends and so suggests that they set out to explore. Firstly, they traverse a swamp and go into a forest where John is the target of giant bats. The Doctor uses a stick to drive them off but he is convinced that somebody evil has trained the bats to attack humans. They cross another marsh via some stepping stones but the stones start sink. Fortunately they find that they can wade through to the other side.

They see a futuristic castle and dodge the portcullis as they enter. Within the castle are not only ghosts but suits of armour wielding axes that they need to bypass. After successfully negotiating these they go into a library which is plunged into darkness. A ghost confronts them but the Doctor sees that it is only an image being projected to trap them. Too late, they are caught in a glass box.

Their captor is Zentor. He has created the Haunted Planet as a cover for his real plan, the development of a gas that he intends to use to poison the atmospheres of all of the planets in the universe. He intends to demand a ransom from everybody but because he has now revealed his plan he is forced to kill the Doctor and his grandchildren. He puts them into a device that will atomize them but the Doctor uses Gillian's mirror to reflect the rays back.

This allows the Doctor to pretend to be his own ghost. Terrified, Zentor runs out of the castle and drowns in the marsh.

The TARDIS arrives in an evil-looking forest on the planet Zerox. The Doctor decides that it looks too dangerous for John and Gillian and leaves them in the TARDIS. No sooner has he set out than he is taken prisoner by the local natives. He is presented to their Emperor and told that he is to be taken to the arena where he must fight various beasts.

When the first monster enters the arena the Doctor is afraid for his life but he manages to fend it off with a sonic beam from his watch. The monster turns on its master which allows the Doctor to escape back to the forest. The natives start a search to kill or recapture him, using dogs. The Doctor, rather fortunately, has come out with his tranquiliser arrows and a catapult but even with the dogs taken care of he is faced with flying chariots. Smoke bombs get rid of two of these but the Emperor decides it is time to kill him.

The Doctor is out of weapons and trapped on a cliff. He has no more options until John and Gillian fly to his rescue wearing jet packs. They lift him to safety. He tells them off for leaving the TARDIS but also thanks them for saving his life.

The TARDIS materialises in the middle of the ocean and promptly sinks to the seabed. Peculiarly, there are no fish in the sea so the Doctor, John and Gillian put on flippers and breathing apparatus and go out to find out why. They are immediately caught by a giant robot. They find themselves inside a chamber within the claw of the robot from where they are taken to meet the Professor who is in the robot's control room (situated in its head). The Professor tells them that the engines in the robot's body are worked by slaves. The Doctor is told that he is in charge of a computer in the engine room and that if he tries to escape he will be killed.

The Doctor's job is to pull a lever every ten minutes or the legs will seize up. Naturally, he decides to let this happen. The robot shudders to a standstill and the slaves attack their guards. The Doctor and his grandchildren use a lift to escape and then sabotage it to prevent anyone following. They try to get out of the robot but the Professor comes after them with a spear gun. He holds them at gun point until the Doctor attacks him and the gun shoots a hole in the robot's skin. Water pours in and they escape. The robot explodes, allowing the slaves to escape. Fortunately they can breathe under water and are full of thanks for the time travellers.

When the TARDIS is pulled off course the Doctor suggests that an old enemy is after them for revenge. This is confirmed when they land in a futuristic city and are caught by their old foes the Trods. The Trods were not destroyed by the Doctor when they last met; merely disconnected from their power source. It wasn't long before someone else came along and powered them up again. Now he has planned a bizarrely complex and fiendish punishment for the travellers to avenge the Trods.

The travellers are shown a plan of the city and told that it is suffused with traps which will require intelligence and skill to survive. The Doctor selects a building to start in: much to the delight of theTrods' new human leader because all of the building's door handles and staircases are connected to explosives. Fortunately, the explosion damages one of the walls and they escape onto the streets.

The Trods see that they have avoided the death that was planned for them and are ordered to kill the travellers before they get to the main control tower. The trio avoids the robots and get into the tower and up to the control room. The new controller of the Trods makes a lunge at the Doctor, misses and falls out of a window. He plummets to his death, leaving the Doctor free reign of the controls. He tells the Trods to destroy themselves in a large furnace, finishing them off for good.

After arriving at a space port, the Doctor, John and Gillian are met by an official who explains that the throngs of people arriving are there for the Galaxy Games being held in their stadium. He escorts them to the stadium where they see a Klondite athlete winning one of the races. Despite this athlete being the leading competitor in the Games, the Doctor thinks that he would be no match for an Earth athlete. He promptly enters John's name as the Earth's competitor.

John races against the Klondite and wins. The Klondite's trainer booby traps the finishing posts so that the winner of the race will be killed by lasers. The Doctor notices the trap and uses a discus to disarm the trap.

Deciding that it would be safer training in the countryside, John leaves the stadium. He is pursued by Klondites who attempt to kidnap him. The Doctor and Gillian find a hut in where the Klondites are hiding in the forest and throw rocks at them to knock them out. John runs back over the country back to the stadium and wins the Galaxy Games, just as the Doctor and Gillian arrive at the stadium to see Earth's great victory.

The Doctor looks at the video scanner to see where the TARDIS has landed. Nothing is visible so the Doctor and his grandchildren go out to explore. They find that they are in a crater and climb to the top. They are taken prisoner almost immediately and are placed in a compound where they are told that, along with other prisoners, they will be used for experiments.

Their captors, the Master Race, decide that they should be used in trials of experimental technology. The Doctor, John and Gillian are all selected but the Doctor pleads for Gillian to be excluded. John and the Doctor are put into a space mobile for a crash test. The experimental seat belts save their lives but their next test is in a military rocket to check the negative effects of long journeys in space.

Once in space the Doctor takes over the controls and turns the rocket back on the Master Race's headquarters. He uses the fuel tanks as explosive bombs, forcing the Master Race escape in their spaceships. The Doctor frees the prisoners and the travellers return to the TARDIS.

A spaceship is forced down on the planet Spekra and the crew is captured by King Gritog. He charges them with being spies. The TARDIS also lands on the planet and the Doctor plans to find and free the captives. Firstly, he has to avoid some large dinosaurs which he manages by playing music on a pipe that is only audible to the dinosaurs. This also makes them attack the guards.

Gritog tells the guards to shoot the dinosaurs but they have armour plated hides. The captives escape to their space ship. Gritog is furious and tries to destroy the TARDIS with missiles but the Doctor uses a magnetic beam to fend off the attack and allow him to continue on his way.

The Doctor, John and Gillian arrive on a south sea island on Earth. There they escape from an erupting volcano and discover King Neptune who rules his domain from inside a giant sandcastle. He gives them a feast in their honour and John opens an oyster and discovers a pearl. When they leave the castle they find that the volcano has become dormant again.

The TARDIS arrives on the planet Zeno. All of the planet's inhabitants have been petrified. There is a legend that tells of the Gorgon coming to this world after leaving Earth. The Doctor gets John and Gillian to put on blindfolds. He then borrows Gillian's mirror and turns the Gorgon to stone. The remaining living inhabitants of the planet come out of hiding to express their gratitude.

Two Earth astronauts lose control of their rocket ship, which is drawn down to the surface of a desert world scorched by an enormous sun.  Leaving the craft, they are almost immediately aware of a machine swooping through the air towards them.  

Soon afterwards the TARDIS lands near the now abandoned ship, beside which is the word HELP written in the sand.  John enters the deserted craft and emerges with a flare gun he has found.  A creature in a flying bubble machine arrives on the scene and bears down on them.  The travellers immediately identify it as a Klepton, one of the race they met and defeated during their first adventure together (The Klepton Parasites).  John uses the flare gun to defend them, the bubble cracks and the distracted Klepton loses control of the machine, crashing it.  The three remove the stunned creature and board the damaged machine, which is still usable.  

Travelling over the desert, they reach a flat-topped pyramid and fly into it via a hatch that opens automatically at their approach.  Unfortunately, the Kleptons are well aware of what has occurred and capture Dr Who, John and Gillian as they leave the bubble craft.

The Klepton leader tells the Doctor that their world has moved too close to the sun and become uninhabitable, and that they need a new home.  They have learnt of the planet Earth and insist that Dr Who helps them to plan an invasion.  When he refuses, he is placed, with John and Gillian and the two Earth astronauts, in a large open-topped crate that is suspended from the roof over a vat of boiling oil.  The sides of the crate are of metal, but the bottom is made of only basket-like lattice.  

The astronauts have also refused their help, but point out to the time travellers that if they all persist in opposing the Kleptons the obvious is going to happen: the crate will be dropped into the bubbling oil.  John, who still retains the flare gun, aims it at the oil and fires.  A thick cloud of black smoke rises from the vat, and John urges his companions to swing the crate back and forth.  They grab the edge of the vat and between them manage to hold the crate there while they all climb out of it.  Under cover of the smoke they board two of the bubble craft and leave by way of the automatic hatch.  

The Kleptons are soon in hot pursuit, but in their haste they omit to reactivate the equipment they used to draw the Earth ship to the planet and hold it there, so the astronauts are able to lift off as the time travellers watch.  Dr Who, John and Gillian have a rather narrower escape, the TARDIS vanishing just as the Kleptons reach it.  Inside the ship, Dr Who expresses the hope that they will arrive at a friendlier place next time.

It is 2035: The Space Police are concerned by a cocoon-shaped spaceship nearing Earth. Before they can respond, the ship emits smaller cocoons that land on Earth. A convention of Earth's lading scientists is interrupted by the arrival of Caterpillar Men. They use beams from their eyes to overpower the scientists and then broadcast a message to the world that they will be using the scientists to conquer the planet.

The TARDIS lands in a jungle on Earth. Straight away, the Doctor is captured by the Caterpillar Men. They incarcerate him with the scientists inside a dome. John and Gillian decide to go for help. They arrive, by chance, at the World Pest Control offices. The pest controllers use helicopters laden with pesticides that kill the Caterpillars (but don't harm humans). The world is saved.

The planet of Int is being ravaged by war between two heavily armed nations. The nation of Ulk launches a boat laden with enough explosives to destroy their enemy's chief city. The TARDIS lands aboard the ship. The travellers explore the ship and find its deadly cargo. They try to leave in the TARDIS but realise that an electrical force field has been activated and they are trapped on board. The opposing nation fires missiles at the ship but they explode when they hit the force field. The Doctor uses one of the ship's masts to steer the ship back to where it came from. The people of Ulk have no option but to disable the force field so that they can destroy the ship themselves. As they launch their missiles, the TARDIS can depart.

The TARDIS lands on a green, jungle planet. As soon as Gillian steps out she is attacked by a strange cat-creature. John drives it off by throwing a stone. A rockfall hits the TARDIS door, preventing it from closing and meaning that they cannot take off again. John and Gillian are chased by a large bird which traps them in a cage before taking them to a large tree where similar birds are waiting. The Doctor arrives with one of the cat-creatures. It chews through the cage bars (which are wood). They escape back to the TARDIS and repair the damaged door.