Selestru has sent Galanar, his most trusted agent, into the Border Worlds to investigate the situation. Under the name of Dr Dennis Grentram, Galanar is working alongside Border Worlds natives Japrice and Mevis in a Healing Zone on the planet Scalanis 8 -- but the Borderers believe that the Union is using the plague as an excuse to keep them under control, and don’t trust their new associate enough to tell him any of their secrets. Selestru thus hasn’t heard from Galanar for quite some time, and he’s willing to listen when Tarkov’s daughter, Amur, volunteers for a dangerous assignment. Her father needs medical attention, he will do whatever it takes to prove that the Daleks are a threat, and it’s clear that Selestru needs more undercover agents in the Border Worlds. Perhaps they can solve all of their problems at once...

On the planet Graxis Major, the last of the free Wardens has been tracked down and exterminated by the Daleks. The few survivors have retreated to their spaceship, Ranger 1, but Kaymee Arnod, who suffered a concussion when she first arrived on the planet and was injured further in their escape from the Daleks, is complaining of aches and pains in her entire body. Culver takes her to the ship’s sickbay for a once-over while Roozell and Chauley prep the ship for launch and Saxton and Telligan pick up weapons from the bunker’s armoury. As they stock up, they feel a minor earth tremor; the Daleks, pressed for time, have begun the initial stages of geoforming the planet.

Provost Carneill and his human crewmate, Antani, catch Saxton and Telligan at the armoury; however, Saxton has calmed down since her earlier confrontation with Carneill, and she realises that he came here without telling the Daleks. Carneill, offended by the implication that he needs to seek the Daleks’ permission before acting, contacts the Dalek commander and reports that he’s found and captured the surviving Wardens -- but the commander immediately sends out a Dalek to take charge of the situation. Carneill begs Saxton to let him take her in, but she refuses; she’s seen through his bluster, and knows that, deep down, he’s still trying to convince himself that the Daleks really are here to help. Frustrated, Carneill tells her just how bad things are out in the Border Worlds; the Daleks and their planetary Healing Zones are the only hope they have of curing the plague, and if that means the destruction of all other forms of life in the Graxis system, it’s a price that Carneill is willing to pay. Nevertheless, Saxton refuses to surrender, and Carneill finds that he can’t bring himself to shoot her; despite all he’s said, some part of him does understand that what the Daleks are doing is evil.

Culver then contacts Saxton with very bad news: Kaymee doesn’t have a concussion, she has the NFS plague. Culver managed to isolate her in a containment suit before she became contagious, but if they take her with them, they’re condemning her to a slow death. It seems that they have no choice but to leave her behind; if Carneill is even telling part of the truth, only the Daleks can save Kaymee now. A Dalek has arrived at the launch pad to deal with the Wardens, and as Telligan and Antani try to delay it, Saxton speaks to Kaymee and breaks the bad news to her. Saxton reveals that she hired Kaymee on a hunch; even though Kaymee had copied her grandmother’s application, Saxton gambled that she wouldn’t have done so unless she understood what she was writing. Somewhat delirious, Kaymee lashes out at Saxton for abandoning her, but in a final moment of lucidity, asks Saxton to contact her father -- Seth Arnod of Tantalus traffic control -- and bid him goodbye. Saxton promises to do so, and she and her fellow Wardens retreat into Ranger 1 and take off, leaving Kaymee with Carneill, Antani -- and the Daleks.

Selestru is reluctant to send amateurs on a covert mission, but Amur manages to convince him that her father’s illness gives them the perfect cover to enter the Border Worlds and investigate on his behalf. With Tarkov’s approval, they sedate him to make his condition appear worse than it is, and Amur gets him aboard a medical supply ship heading into the Border Worlds -- though fully aware that once they’ve crossed the frontier they won’t be permitted to return. Nevertheless, she claims that she was alone in the world until her father returned, and promises to do whatever she can to help him. As the sedative wears off, Tarkov asks Amur whether his wife suffered in the crash that took her life, but Amur can’t answer that question; instead, she leaves to fetch food from the galley, telling Tarkov that they’ll talk when she returns. In the corridor outside, she meets a crewman who politely points out that she’s heading in the wrong direction. But once he’s gone, she continues the same way -- not towards the galley, but towards the ship’s crew deck and communications unit...

Elsewhere, the Daleks are monitoring the Variant 7 trials when Mevis approaches them with concerns about “Dr Grentram” -- who has mentioned the Daleks by name. Japrice thus takes Galanar to Ward V-7, a ward of terminal patients who are now in the stages of a full recovery. Galanar notes that the patients’ IV tubes are connected directly to the ward’s infrastructure, but Japrice does not tell him where the tubes lead. She orders him to monitor the patients’ condition; if they remain stable by the end of his shift, then mass inoculations can begin. Japrice then reports to the Daleks, who intend to monitor Galanar to find out what kind of security risk he poses. However, Galanar disappears entirely from the security monitors, and by the time they locate him again, his brain is showing inhumanly high levels of electrochemical activity -- and he’s following the Variant 7 supply ducts, even though he shouldn’t be able to perceive them through the wall. The Daleks dismiss Japrice and Mevis and take charge of the situation, and when they report to the Dalek Supreme, she orders them to capture the intruder before he puts Dalek operations at risk.

Back in the Galactic Union, Giorgi Selestru is summoned before Bulis Meitok and ordered to release all information on his current covert ops missions. When Selestru tries to evade the order, Meitok reveals that the Security Committee has been keeping Selestru under observation, and they’re aware that he’s fast-tracked permission for Siy Tarkov and Amur to enter the Border Worlds. Meitok then drops a bombshell: Siy Tarkov’s daughter died in the same crash that killed his wife. Whoever the woman is with Tarkov, it isn’t his daughter, and Selestru was so determined to prove himself right about the Daleks that he didn’t bother to check her credentials. Selestru is now in a great deal of trouble, as his actions could pose a threat to the stability of the Galactic Union and Meitok will do whatever it takes to keep the peace. Selestru insists that his actions were justified to protect the Union from an external threat, but he’s nevertheless forced to reveal the details of his other mission -- including the whole story behind Galanar, who’s far more than a mere security agent...

The Dalek Supreme has analysed the reports on “Dr Grentram”, and has realised who -- and what -- he really is. On her instructions, the Daleks seal off the area where he was last sighted; he is currently evading visual detection, but can’t do so for long without becoming exhausted. When he tires and becomes visible, the Daleks are to capture him -- alive. Meanwhile, Galanar is working his way through the warrens of the Healing Zone, trying to avoid the patrolling Daleks (which he finds oddly familiar) and find out how they’ve managed to produce a cure for the NFS plague so quickly. As the Dalek Supreme predicted, however, he is becoming more and more exhausted and light-headed, and finally, slightly delirious, he gives up hiding and simply runs for the centre of Dalek operations to find out what he can. He fuses the security pad with a touch, opening the bulkhead to the secure zone -- but what he sees in the moments before he is captured makes no sense...

The Wardens touch down on Tantalus so Saxton can contact Seth Arnod as promised. Tantalus is also under Dalek control, but Saxton evades the patrols and manages to contact Seth. Though horrified to learn that Kaymee has caught the plague, Seth understands that Saxton did her best for his daughter. He too fears the Daleks, and he therefore supplies Saxton with data on Dalek movements that he downloaded from Tantalus traffic control -- enough information to allow the Wardens to evade the Daleks for some time. Saxton invites Seth to flee with them, but he refuses, as his disappearance would alert the Daleks to his theft of the traffic data. Saxton is forced to retreat when a Dalek patrol happens by; fortunately, they fail to notice her, and Seth manages to convince him that he just left his station for a breath of fresh air. Though suspicious, the Daleks allow him to return to work, ordering him to monitor his health at all times.

“Amur” emerges from the medical ship’s communications deck, and when she is spotted by the same man who saw her earlier, she simply kills him without a word and returns to Tarkov’s room. There, she slips back into the mode of the grieving daughter, but while speaking with Tarkov, she questions whether the Daleks really are as bad as he claims, as his only evidence comes from a discredited scientist and psychic impressions from {a man who died centuries ago}. Tarkov reminds her that he’s heard a Dalek transmission confirming their intention to conquer the galaxy, but she in turn reminds him that he’s suffering from a plague that causes brain damage; can he really be sure of what he thinks he heard? At that moment, alarms sound throughout the ship, and Amur heads to the bridge to investigate. Another ship jams the medical ship’s communications and destroys their solar sails, preventing them from fleeing -- and the Daleks then contact the ship’s captain and order him to surrender...