London, England. A telephone call wakes Paul Hunt and his lover Samantha at 3:00 a.m., but the irritated Hunt snaps to attention when the man on the other end says a single word: “Scorpius.” Hunt tells the bewildered and angry Samantha that he’ll have to leave now, and that he may not be coming back. Soon, Hunt is on his way to the Isle of Wight, where Vice-Admiral Charles Hendry reveals that they’ve found what they were looking for, five miles out and thirty fathoms down. The last time they tried something like this, it didn’t go very well -- but the Orion war has taken a turn for the worse, and they’re desperate enough to try again. Hunt assumes at first that they’ve found a scrap of technology, perhaps a flight recorder, but when he and Hendry arrive at their destination he learns that Scorpius has found much more than that...

The Orion war is going very badly for humanity. Planetary Assault Force Delta on Orius Beta VIII has walked straight into an ambush, but Admiral Karen Brett isn’t moving in until she gets the information she needs from the traitor Helliton. He’s the one who tampered with the intelligence reports and thus sent Delta to their deaths... but Brett suspects that this is only part of the androids’ plan, and that the Android Eighth Fleet is hiding in the system, waiting for the humans to launch a rescue attempt. Helliton claims that this is not the case, and Brett thus switches on the torture devices, driving bolts of pain through every nerve ending in Helliton’s body. She assures the agonised Helliton that he’s entitled to his opinion that the androids are deserving of life... but that doesn’t change the fact that he swore allegiance to his comrades, and then sent thousands of them to their deaths because they made the mistake of trusting him. Brett demands the decoding frequency for the androids’ scanner shield, and this time, Helliton gives it to her.

Back on Earth, President Duncan Levinson’s aide, Glaust, reports that 50,000 soldiers have died on Orius Beta VIII -- and that Brett has pulled off a tactical victory. According to comms officer Nash of the Redoubtable, Brett forced her people to stand by and wait even though they could hear their comrades dying -- but she got the information she needed in the end, and when the human ships recalibrated their sensors, they saw the android forces hiding behind a scanner shield, just off Orius Beta V, waiting to attack. If Brett had launched her rescue attempt, the human fleet would have been wiped out; as it is, they flanked the android fleet, destroyed it, and then nuked Orius Beta VIII from orbit, assuming -- hopefully with just cause -- that there were no human survivors on the planet at the time. The story has already hit the news media, and despite Levinson’s disgust at Brett’s methods, he can’t deny that the man she tortured to death was responsible for the deaths of thousands. The people see Brett as a hero, and it seems that Levinson has no choice but to bow to their will and appoint her as the new Commander-in-Chief of Earth’s forces. But he’s left with one nagging question: is victory at any cost the future of the human race?

Brett is the only one not celebrating her victory, and despite the attempts of her old friend Captain Liam Barnaby to cheer her up, she admits that she’s starting to have second thoughts about the butchery involved in this war. As her ship sets course for Earth, she receives a mysterious call on her secure line directing her to the planet Reticek IV. Brett decides to keep the appointment, but makes sure that Barnaby and a surveillance team are watching her from a distance, ready to move in at the first sign of trouble. Despite their close surveillance, however, the man who contacted her, Paul Hunt, suddenly appears before her as if from nowhere -- and the surveillance teams find themselves unable to break through the electronic jamming that he’s set up. Frustrated, Barnaby tries to slip closer, but can only hear bits and pieces of the conversation; Hunt is telling Brett about a project called Scorpius, something that developed out of the failed project known as the Sword of Orion...

According to Hunt, President Levinson’s predecessor launched Project Scorpius -- named for the mythological scorpion that killed the hunter Orion -- when the war began to go badly. Levinson refuses to accept that humanity will have to go to great lengths to win this war, but Hunt claims that his people have been watching Brett and have recognised that she knows what it will take to win. There have been no anti-war protests in the week since her “victory” on Orius Beta VIII, and yet Levinson hasn’t bothered to thank her... so perhaps it’s time he was replaced, and who better than the new Commander-in-Chief of Earth’s forces? Hunt vanishes into thin air, and Barnaby rushes up, realising too late that Hunt was never here; Brett has been speaking to a holographic projection. As Brett and Barnaby study the projector, it suddenly flashes into life again, revealing a schematic that looks like a man in some kind of all-encompassing cybernetic battle armour. Even in a still photograph, there’s something awe-inspiring and terrifying about the figure...

Upon returning to Earth, Brett is summoned to the White House to speak with Levinson, but it takes her a while to get there, since she’s at the head of a victory parade. The people are happier now than they have been for 20 years, and it’s all because of Brett; thus, the media naturally assume that Levinson is trying to be seen with her in order to boost his own fading popularity. Levinson isn’t pleased about that, but as a politician, it’s his job to judge the mood of the crowd -- and since he can’t give them an outright victory, he informs Brett that he’s decided to appoint her as his new Commander-in-Chief. Brett hesitates, perhaps thinking of Hunt’s cryptic remarks, and then accepts the position -- and at that very moment, a shuttle crashes into the grounds of the White House and armed figures in spacesuits storm the building, catching the security forces entirely off guard. The figures shoot Glaust and Levinson before Brett’s eyes, but they do not kill Brett; instead, the lead figure -- speaking in a modulated electronic voice -- informs her that she will now become the new President of Earth. Brett demands an explanation, but the attackers shoot her and then depart, leaving her stunned but alive.

The attackers have escaped using a transmat system with an energy signature unlike anything the human forces have ever seen. In the aftermath of the President’s assassination, the Senate invokes emergency powers and appoints Brett as Levinson’s replacement -- just as Paul Hunt had predicted. She in turn appoints Barnaby her Commander-in-Chief; together, they are confident that they can turn the tide of the war. But their confidence is misplaced. Over the next several months, the situation in Orion deteriorates, as the androids change their tactics and begin killing human civilians as well as soldiers. Brett refuses to accept defeat, convinced that she’s fighting to preserve her people’s future against creatures that are less than human -- and eventually, she begins to wonder what the mysterious Project Scorpius has to offer.

Once Brett has reached this point, one of Levinson’s assassins beams directly into the White House and heads for Brett’s living quarters, where it locks itself in with her and removes its helmet to reveal that it is one of the cybernetic warriors she saw in the hologram on Reticek IV. The figure reveals that Levinson was killed in order to grant Brett the Presidency, because she’s the kind of person who will do whatever it takes to win the Orion war. It then gives Brett a holographic projector, and beams out moments before Barnaby breaks down the door and bursts in. For the first time in her life, Brett lies to her friend, claiming that the figure didn’t speak to her; she’s desperate now, and needs to know more about Scorpius -- and what it can do for her -- before she’ll feel ready to confide in Barnaby. Following this incident, Barnaby has the White House’s security scanners recalibrated, but the transmat used by the figures was set to a frequency that neither the humans nor the androids have the technology to utilise yet...

The war continues. Brett faces opposition from protestors who insist that she’s allowing millions of innocent people to die because of her stubborn refusal to negotiate peace terms; however, she remains committed to the fight, and continues urging her people to remain steadfast against those who would destroy all that humanity means. Sadly, strong words aren’t enough to hold back the androids -- and one day, Barnaby must deliver some terrible news. The androids launched an unprovoked assault on the undefended Vaslovian system, killing millions of human civilians... including Karen Brett’s parents. Brett tries to be strong, but she can’t keep up the façade for long in front of Barnaby; her parents were unable to attend her inauguration because of wartime travel restrictions, but the last time they spoke, they told her how proud of her they were. Now they’re dead because the androids aren’t fighting by the rules; they don’t just want to win, they want to destroy humanity’s will to win. But now the last of Brett’s reservations have gone, and she’s willing to do whatever it takes to destroy the androids forever... including turning to Project Scorpius.

All official files on Scorpius have been deleted, on the orders of the late President Levinson. Brett thus uses the holographic projector provided by her cybernetic visitor to contact Paul Hunt once again. He’s aware that she hasn’t told anyone else about her encounter, and he knows why, even if she doesn’t; a good leader must stand alone, without friends or family, and must be willing to act whatever the cost. He urges Brett to imagine an army of cybernetic warriors marching on the android hordes and wiping them out; it’s within her power to make this vision a reality. The projector contains a transmat chip keyed to Brett’s DNA; if she shuts down the security scans that Barnaby has installed, she can use it to find out exactly what Scorpius has to offer. But if anyone else tampers with it or scans the transmat beam while it’s in use, then it will self-destruct, and Brett will lose her only chance to win the war. Hunt’s image vanishes, leaving Brett to think it over... and back in Scorpius base, Hunt assures the Cyber-Planner that all is going as they had predicted. The deaths of Brett’s parents, while unforeseen, has played directly into the Cybermen’s hands, turning Brett’s desire for victory into an obsession that will deliver her to Scorpius.