Maggie and Skredsvig are worried about their friend Edvard, who has seen a terrible vision while walking along the road with friends. They noticed nothing different, but to Edvard, the sky turned to coagulated blood, striped with tongues of fire, as an infinite Scream tore through nature. Edvard still has the Scream in his mind, and it’s driving him mad, but Skredsvig has advised him to do what he does best -- paint the image in his mind, and try to exorcise it onto canvas. Centuries in the future, there are different screams on another planet; the dust of Duchamp 331 is hammering at Refueling Station B, and technician Jay Binks is the last one left alive. Even as he tries desperately to contact Duchamp control, the dust smashes through the window and comes for him, to smother him as it has all the others...

Ace finds the Doctor in the TARDIS art gallery, which is filled with paintings and sculptures from all parts of the galaxy. She is impressed until she discovers where the Doctor acquired his collection; he nips into art galleries moments before History records their destruction, and “rescues” the paintings. He claims that returning them afterwards would change the course of history, but to Ace it’s tantamount to grave robbing. Nevertheless, the Doctor intends to pop off to Duchamp 331, where, according to history, Edvard Munch’s “The Scream” is about to vanish in mysterious circumstances. Duchamp is located in the middle of a major shipping route and has become an important refueling point; the stations sit atop massive tanks buried in the dust which covers the entire world. As the Doctor and Ace approach, they pick up a distress signal, and materialise in Refueling Station B. The base has been torn apart by severe storm winds, and there’s a strange screaming sound in the air as the dust storm batters the station. At first they seem to be too late, but Ace finds Binks barely alive under the wreckage, and they get him into the TARDIS moments before the remains of the station collapse around them. Binks is delirious, and passes out mumbling warnings about the dust. Perhaps the Doctor should have done a bit more research into those mysterious circumstances....

Bev Tarrant is also on Duchamp 331, and she’s been stranded here for some time. She burned out her ship’s hyper-drive escaping from the border patrol after stealing a priceless idol out on the frontier, and although she’s had it repaired she is now unable to afford the fuel to get off the planet. She gets a sympathetic ear from Guthrie, one of the first humans to arrive on Duchamp 331; most people get off this planet of dust as quickly as they can, but Guthrie has always extended his tour of duty, and claims that he’ll die here. He has some rather strange habits; although he doesn’t smoke, claiming that it’s a dangerous habit on a refueling station, he still carries a cigarette lighter around for sentimental reasons. Bev is already bored with the routine of the planet, and doesn’t see how Guthrie can stand it -- but then the routine is overturned when the TARDIS materialises, bringing Bev’s friends Ace and the Doctor, with a man in need of serious medical attention. Bev helps them to get Binks to the sickbay, where the Doctor keeps an eye on him while Bev and Ace retire to the bar to catch up on their adventures after Kar-Charrat.

Elsewhere, the opulent starship Gallery is preparing to depart for its adventure cruise to Duchamp 331, but its departure is delayed by the late arrival of a passenger. Madame Elsa Salvadori is perfectly willing to leave him behind, at least until she learns that the tardy passenger is the mysterious Mr. Seta, who is helping to fund the journey. When the voyage gets underway, Madame Salvadori addresses her passengers and patrons; this cruise will give them the opportunity to bid on priceless works of art and witness a specially commissioned piece which will make their purchases pale in comparison. Mr. Seta assures Salvadori that his treatment has been most satisfactory, but she still isn’t satisfied by her inability to learn anything about his past. Her assistant Klemp has been unable to learn anything about Mr. Seta -- who he is, what debilitating condition he seems to be suffering from, or how he can afford a face mask encrusted with jewellery worth over three million. Salvadori vows to learn the truth about her mysterious patron -- but she’s going to regret it when she does...

Ace asks Bev about the strange screaming in the air, and Bev explains that it’s the sound of the native dust sharks. Guthrie has a far more interesting tale to spin, however; according to legend, a Dalek saucer crashed on Duchamp 331 long ago, and before they could make repairs the dust sucked them straight down and buried them forever in the dark. The screams are the sound of Dalek madness, carried on the wind. The Doctor arrives and warns Ace that the commander has asked them to stay on the planet until the investigation into the destruction of base B is complete; in the meantime, the dust storm seems to have eased, so they’ll visit the artists’ colony -- the so-called Outhouse. Bev offers to take them there, hoping to offload some of her “merchandise” with its leader, Damien Pierson.

The twitchy and rather consumptive-sounding Damien has just completed a rather distressing conversation with his patron, Madame Salvadori; he claims that the sketch for his work was satisfactory, but she still threatens him with dire consequences should the full work not be ready when she arrives in three hours. In the meantime, Damien welcomes his visitors to the Outhouse, which was assembled from cannibalised parts of each new artist’s ship. Ace is delighted by the wide variety of art on display, but before the Doctor can find what he came here for, Bev receives a call from the main base; Binks has died, and the commander wants the Doctor back right away. Ace offers to stay in the Outhouse, and the Doctor departs, warning her to keep her eyes open for any mysterious circumstances. Damien shows Ace to the gallery where he keeps the historically valuable artwork, and, seeming pained by her brash enthusiasm, he leaves her to explore while he returns to his own office. Ace soon locates “The Scream”, but as she studies the painting it seems to affect her more deeply than she’d expected. Within seconds she’s writhing in pain, screaming herself as an ancient force pummels at her mind. She is being psychically attacked by the painting itself...

Security guard Albert Bootle is checking the hold of the Gallery and complaining to himself when he spots movement in the shadows. Mr. Seta is here, checking on his cargo, and although respectful, Albert nevertheless insists that he’ll have to report Mr. Seta’s presence in a restricted zone to his captain. This proves unfortunate for Albert. Some time later, his corpse is discovered in a gruesome condition. Klemp reports to Salvadori, and as the body is taken away, he assures her that none of the cargo has been stolen -- but it seems that whoever killed Albert was tampering with Mr. Seta’s mysterious crates.

The dust jams the door controls within seconds, trapping the Doctor and Bev in the sickbay; but it takes the Doctor only a few more seconds to pry open the air conditioning unit and reverse its polarity, sucking all of the dust out of the room. Binks collapses, all of the fluid in his body having been replaced by the dust which has now been vented outside. Guthrie arrives to find Bev shaken by her experiences, and once again offers her a light despite the risk posed by smoking on a refueling station. While Guthrie cleans up the sickbay, the Doctor and Bev return to the bar to discuss the attack; it seemed curiously elaborate, as though the dead man were putting on a theatrical performance. It seems that the dust was deliberately trying to kill them, but the Doctor doesn’t think the dust itself is a living entity; rather, he suspects that someone or something may be manipulating it telekinetically.

Salvadori and Klemp have hushed up the news of Bootle’s murder, and have locked his remains in Salvadori’s safe. As Klemp sees to the investigation, Mr. Seta speaks privately to Salvadori, apparently to ensure that all is running according to schedule. He has a personal interest in seeing that this voyage is a success, and although Salvadori assures him that all is well, she is fully aware that his charming words mask a quite pointed threat. And she doesn’t take kindly to threats.

Ace staggers out of the gallery, the painting’s rage still hammering at her mind. Once out in the corridor she begins to recover, but she’s still shaken and angry, and she sets off to confront Damien. Oddly, there doesn’t appear to be anyone around who can direct her to his office, but she finds it herself eventually -- and sees him monitoring the Doctor and Bev as they discuss the strange events. Damien clearly knows more than he’s saying, but even so, Ace has underestimated his madness; convinced that he’s about to create a work of art which will make him immortal, he stuns Ace and drags her back to the gallery. He knows that something is lurking in the painting, something he claims to find inspirational. Ace tries to convince Damien that it’s just using him, but he refuses to listen; he knows that she can’t hope to understand what he hopes to achieve until she communes with his inspiration as so many others have before her. Still weak from the stun ray, Ace can’t stop Damien from locking her in the gallery, or resist as the Scream forces its way into her head again...

If the Doctor’s suspicions are correct, the refueling station’s destruction was deliberate; but why would anybody wish to destroy one of the six bases on this planet? There are never more than 100 or so employees of the Duchamp Corporation here at any given time, and then there are the fifty or so artists in the Outhouse -- although the Doctor found it surprisingly deserted when he visited. Guthrie gloomily prophesies that things will get much worse, and although Bev dismisses his tall tales, the Doctor realises that he’s speaking from experience. Guthrie admits that the cigarette lighter he carries used to belong to his partner, Burton; one day, while they were out trawling for dust sharks, the dust rose up like a living thing and dragged Burton down with it. All Guthrie ever rescued was his lighter. There are always blood feuds out on the frontier, and the Corporation turned a blind eye to Burton’s death, assuming that Guthrie had killed him but not caring very much. Guthrie has never forgotten, and he has been extending his tour of duty ever since, always looking for an answer, waiting for a chance to avenge his partner’s death, knowing that he too will die on Duchamp one day...

The Doctor is surprised when Guthrie reveals that the Outhouse was here even back at the start, and decides that Damien requires closer investigation. He asks Bev and Guthrie to stay at the base and keep an eye on things; like Guthrie, he believes that the storm coming isn’t just a literal one. He pilots the TARDIS directly to the gallery, arriving just in time to save Ace; her encounter with the Scream has left her badly shaken, and she knows that whatever is trapped in the painting is something evil. And she suspects that she isn’t the first person Damien has locked up with it. There are supposed to be fifty people in the Outhouse, so why couldn’t she find anyone when she was looking for Damien earlier? The Doctor approaches the painting, and introduces himself to the thing in the Scream, trying to find out what it is and how long it has been influencing those in the world around it. He tries to speak calmly and reasonably, but the power hammering at his mind seems intent upon taking what it wants by force...

As Bev and Guthrie wait to hear from the Doctor, the control tower detects a fancy-looking ship entering orbit. It’s not on any of their flight schedules, so what’s it doing there? Guthrie suspects that things are going to get a great deal worse before this is over...

The Scream fights its way into the Doctor’s mind, and as he struggles to contain it he tries to manipulate it into telling Ace all about itself. It’s quite happy to do so; it is the ultimate weapon, the scream of the madman, every death Ace can ever imagine. It is the Warp Core, built to protect its creators from an unstoppable and indiscriminate weapon -- but as is so often the case, its creators found that they had made something too powerful and terrible for them to control. The Warp Core fled from them, wounded and weary, and sought refuge in the mind of an artist on the planet Earth; but the man’s mind snapped at its touch, the Core was tainted with his madness, and somehow, the artist exorcised the mental energy which had possessed him into his painting. The Warp Core has been dormant within the painting ever since, but now it has woken again, for its ancient enemies are approaching and battle will soon be joined. It cannot waste time or energy struggling with the Doctor, so it releases him and retreats back into the painting, waiting. Shaken, the Doctor takes Ace out of the gallery to try to talk sense into Damien. He now knows enough to understand that Damien is about to unleash a power which could destroy all life on this planet.

Salvadori’s patrons gather in the ballroom of the Gallery to witness the unveiling of the great artwork which Salvadori has commissioned -- but they get more than they bargained for when the lift doors open and the Krill burst out. The terrified Salvadori flees to her cabin, where she finds Klemp under the thrall of the man she knows as Seta. The Master applauds her self-interest in abandoning the others to their fate, but scoffs when she expresses horror at what he’s done. Salvadori sees only masks; blinded by her passengers’ wealth and power, she never thought to ask how they acquired it. The late passengers had secrets which would have stunned her, and the Master now removes his own mask to reveal a face which is an image of horror. Unlike Salvadori, he does not flinch from what he has to do to gain power, and unleashing the Krill upon the passengers and crew of the Gallery is only part of his plan. On the planet below is a force which makes the Krill look like toys, and the Master is going to let it loose. Even under the Master’s thrall, Klemp is too loyal to act against Salvadori, but the Master forces Salvadori to do as he demands by threatening Klemp; if she doesn’t obey, she will have another shrunken corpse to join the one already in her safe. She thus contacts Damien and orders him to begin his work; his audience is waiting. Now all they have to do is wait; soon the Master will show Salvadori what real power is...

The Doctor now knows his enemy; or one of them, at least. The Warp Core is pure mental energy, primed with hatred and the desire for destruction, designed to protect its creators from the Krill. It worked too well, and after destroying its own creators it fled to Earth and hid inside an artist’s mind, only to be exorcised into his artwork. Ever since then it has lain dormant, influencing those around it while waiting for the chance to strike out against the Krill once again. Damien is part of its plan, but what is he providing for it? Before they can find him, Bev arrives to warn them that the storms have suddenly subsided; but the sharks are screaming through the dust, as if they can sense something coming. The Doctor realises that Damien intends to release the Warp Core into the dust; the destruction of the refueling station was only a preliminary sketch for the great artwork. The Warp Core can manipulate the dust telekinetically, and when Damien releases it, it will control all the dust on the planet. The Doctor sends Bev and Ace back to the main base, ordering them to get everybody off Duchamp immediately. They’ll have to make for the ship which has just arrived in orbit; they may not know what it’s doing there, but it will soon be far too dangerous to stay on Duchamp...

The Doctor finds Damien staring out at the dust -- a blank canvas waiting for his artistic vision to bring it to life. Damien knows full well that the Doctor thinks him mad, but that’s only because the Doctor hasn’t seen his vision. Damien proudly shows the Doctor the artists whom he claims joined him of their own free will, happily participating in the creation of a masterpiece. But the Doctor suspects that they never realised their contribution would consist of being strung up in sensory deprivation tanks, their minds and feelings erased, creating a web of mental energy through which Damien will channel the Warp Core into the dust of Duchamp. The Doctor desperately tries to talk sense into Damien, but fails, and must flee to the TARDIS as Damien joins himself to the mental web and releases the Scream into the planet’s dust. Having failed to prevent the Core’s release, the Doctor can only join his friends on the orbiting ship and wait to see what will happen next...

Everyone has evacuated from the planet, except for Ace and Bev. They’ve told Guthrie what’s going on, and assume that he boarded a shuttle and got away... but they’re wrong. He’s hiding in the base, waiting for them to leave, for he understands now what he has to do. The Core is then released into the dust, and a screaming storm whips up around Ace and Bev as they flee for Bev’s ship. She’s stolen the fuel she needs to get away, and she and Ace escape moments ahead of the Core’s arrival. Bev pilots her ship into orbit and docks with the pleasure liner, but when she and Ace emerge into the docking bay, they find it strangely deserted. The evacuees should all be here by now, but there’s no sign of them -- until Tarrant finds the shredded body of the base commander, Frederickson. Ace realises, far too late, that the Krill are here with them...

The Doctor and the Master have crossed paths yet again, as it seems they always will. Past experience leaves the Master unsurprised that the Doctor has survived the attention of the Warp Core, even though the Master himself wasn’t quite so lucky. He can, however, take comfort in knowing that the Doctor has unwittingly sent his companions to their deaths -- or so he thinks. In fact, the Krill in the docking bay ignores Ace and Bev in favour of the hatchway leading out to space, and the women flee moments before the Krill claws its way through. The docking bay bulkhead seals itself behind them, cutting them off from Bev’s ship -- and trapping them in the corridors of the ship, with the rest of the Krill...

The Master stops the Doctor from investigating the hull-breach alarm, preferring that he should witness the Master’s triumph. He knows he can’t control the Krill, and he doesn’t intend to; he simply brought a few of them here to goad the Warp Core into life, after arranging for the Core to be brought here -- its home world. Duchamp 331 was once teeming with life before the Core blasted it to dust. The Master himself felt a trace of that power, when he tried to steal the Scream from an art gallery; the guards and alarms posed no difficulty, but the Master had underestimated the rage of the Core itself, which had been resting peacefully until the Master disturbed its slumber. The Core thus stripped his borrowed Trakenite body from him and reduced him to his former corpse-like state before returning to sleep. The Master was forced to lay other plans, and thus he sold the painting to Damien and arranged for him to establish an art colony here on Duchamp. For years he’s been waiting for this moment; the Core has been let loose, and when it has exhausted itself battling the Krill, the Master will be able to capture it at last, slave it to the heart of his TARDIS, and force it to do his bidding. Soon he will have a new body again, and then, total control over the Universe. The Doctor is disgusted, but there appears to be nothing he can do to stop the Master. Their game has reached its end at last...

Bev and Ace find the shaken Salvadori, who has been trying to find somewhere to hide ever since Seta banished her from her cabin. Everyone else on the ship is dead, apart from Klemp; as far as Salvadori knows there are only three Krill remaining on board, but Ace knows that three is more than enough. They have to find the Doctor quickly, as the TARDIS is now the only way off this ship. As they make thir way towards the lifts, they see the planet through the viewing port; it appears to be growing limbs made of dust, as the Warp Core reaches out for the Krill. The Krill which tore its way out of the docking bay must have sensed its approach, and tried to attack or escape its ancient enemy. Just as the three women reach the lifts, a Krill attacks Salvadori. Ace tries to flee, knowing from bitter past experience that there’s nothing she can do, but Bev refuses to abandon Salvadori to save her own skin and runs screaming at the Krill. Much to Ace’s shock, the Krill actually turns and runs away, giving Salvadori the chance she needs to escape into the lift with Ace and Bev...

Guthrie orders the base computer to initiate an emergency purging operation on all fuel tanks in every station on the planet. As he waits patiently, the dust closes in on him; the Warp Core has sensed his presence, and is curious to know why he hasn’t run screaming like everyone else. It is greatly amused when it realises that he actually intends to destroy it -- he knows it to be the thing that killed his partner, and he actually seems to believe that his feud is significant when compared to the rage of the Core and the Krill. The Core dismisses him from its attention, intending to kill him as soon as it’s done with its real enemies. But Guthrie vows that it will rue the day it turned its back on him...

The Master is ready to take the Core, but first he intends to have Klemp dispose of the Doctor at last. Beofre he can do so, Ace, Bev and Salvadori arrive -- and as Ace learns at last that the Master is behind all of this, dust tendrils begin to lash at the observation window. The Core speaks to Salvadori directly; Damien is now a part of it, and it remembers the hate he felt for her patronising attitude. Likewise, it has nothing but contempt for the Master, who tries to prove his mastery over his human puppets by ordering Klemp to kill Salvadori. Klemp’s loyalty is too strong, and he refuses to do so. Enraged, the Master tries to grab the gun, and Klemp is shot and killed as they struggle. The Core tires of this byplay and smashes through the observation window. Realising that the Core is not under his control, the Master retreats to his TARDIS, which has taken the shape of an ornate pillar in the ballroom; the others flee into the lift moments ahead of the depressurisation.

There are still Krill on the loose between the Doctor and the TARDIS, but when Ace tells him that Bev frightened one off, he realises that their clothes are covered in dust from the storm -- dust which is now imbued with the power of the Warp Core. If they collect enough of it, the Doctor can manipulate it telepathically and use it to drive the Krill away. It takes all of his effort to control the dust, however, and Ace and Bev must drag him to the TARDIS -- and, despite the Doctor’s best efforts, it becomes clear that they aren’t going to make it. Salvadori, blaming herself for the carnage and for Klemp’s death, throws herself to the Krill, giving Ace and Bev enough time to get to safety.

In the TARDIS, as Bev mourns quietly for Salvadori, Ace operates the scanner to reveal that the entire surface of Duchamp 331 is writhing as though alive, which it is. The Doctor hopes to use the telepathic circuits to manipulate the dust on a larger scale and force the Warp Core back to the planet, but to do this he must battle with the mind of the Master, who is using his own TARDIS’ telepathic circuits to draw the Core to him. As they struggle with each other, the Core fights them both, refusing to be trapped again. And while it’s distracted by the fight, it isn’t paying attention to Guthrie, or to the refueling stations -- which have vented all of their thousands of tonnes of fuel into the atmosphere of the planet. At last, Guthrie’s feud is at an end; he always knew he’d die on Duchamp. Before the Core realises what’s happening, Guthrie takes out his late partner’s cigarette lighter and flicks it, igniting the fuel-soaked atmosphere and triggering a chain reaction which destroys the entire planet.