Andromeda arrives at Galena, a former mining world that has been converted to a resort, and is in a relatively secure part of space. There is a conference taking place on Galena, to discuss the fight against the Magog, and Dylan has arranged for Harper to be the keynote speaker. There has, however, been word of an assassination attempt at the conference.

Some unannounced visitors come onboard the Andromeda, and they have her access codes. Rommie identifies them as High Guard bailiffs, with full clearance, but Dylan is annoyed that they did not clear things with him.

While Harper is preparing his speech for the conference, Andromeda receives a message: Professor Wel-Dar, one of the key conference attendees, is missing, and presumed kidnapped.

While the Bailiffs are searching the ship, Dylan corners one and demands an explanation. A second interrupts, with a gun drawn, but Dylan overpowers him. The Bailiff identifies himself as a member of Commonwealth Intelligence, and insists he has the right to inspect the ship. He also claims to have a summons for Dylan. He produces credentials, and Rommie verifies them.

Dylan checks the message provided from Tri-Lorn, who tells him that there is a vital debriefing on a security matter that Dylan must attend. Dylan informs Harper that he must attend the conference without him. Harper insists that he needs Dylan's diplomatic skills, because of higher academics' lack of social skills, but Dylan assures him that he will manage. Dylan is suspicious of the timing of the summons, but feels he needs to know what is going on. He goes with the Bailiffs, but asks Rommie to send a courier ship to follow him.

Beka takes Rommie and Harper to the planet in the Maru. Harper is nervous about his speech and the disappearance of Wel-Dar.

The Bailiffs inform Dylan that they are members of the Special Collections division, and they confine him in a room, out of communication with the Andromeda.

At the conference, the urgent matter of the Magog threat is being discussed. Harper, accompanied by Rommie, meets Doctor Professor Kor-Kavo, who offends Rommie by calling her an "artifact". Harper meets a variety of other scientists, who are also interested in Rommie as a machine. Kor-Kavo introduces Professor Bu-Habib to the conference, but when he begins to speak, his words are unintelligible, and he collapses, dead. Trance examines his body, and discovers evidence of extensive recent micro-surgery in his brain. Some of the other scientists suggest that he may have had work done to give him an advantage in academic and scientific competitions.

The courier sent to follow Dylan returns – he lost Dylan's trail because the Bailiff's ship deployed several decoys in slipstream. Beka tries to contact Tri-Lorn, but he is unavailable, and she can only leave a message. Trance informs Beka that she is certain that the damage done to Bu-Habib's brain was deliberate.

Dylan addresses the mirror in his room, clearly believing that he is being observed. He throws a wine bottle, breaking the mirror, and revealing a Collector behind it. Dylan demands to see his superior, but the Collector begins to interrogate him. Dylan tries to walk out, but he is stopped by an automated security system.

Harper is discussing the Magog with several scientists, but Rommie interrupts to tell him that Kor-Kavo is missing. Just after she says this, Kor-Kavo stumbles into the room and collapses, with a trickle of blood coming from her nose.

Trance revives Kor-Kavo, and she seems to be OK, but she is unable to say what happened to her, other than that she was chased. Beka tells Harper, Rommie, and Kor-Kavo to stick together. Kor-Kavo seems to have taken a liking to Harper, and he does not know how to take it. She leads him off into a side room.

The Collector's ship reappears in the system, but is heading straight for the sun, and is destroyed. Trance insists that he is not dead, and Rhade says that they must keep searching, but Beka says that they should act as if they believe he is dead, in order to find out what is going on. Rhade protests, but Beka asserts her authority.

Rhade observes that the ship passed on the other side of the planet, and that those on the ship could have left it when they were unobserved. Beka agrees to focus their attention on the planet.

Kor-Kavo takes Harper into a dark room, where they find one of the scientists, Ler-Near, dead, with the top of his head removed and his brain exposed. Kor-Kavo sedates Harper.

The Collectors, still holding Dylan, ask him to work with them. Dylan objects to their methods, but asks for more information. They tell him that he will keep his current position, but they will ask him to help eliminate threats identified by them. They threaten to kill him if he does not cooperate, but he refuses.

Rommie finds Harper and Kor-Kavo in the room. Kor-Kavo claims that she found Ler-Near and was attacked by unknown assailants, and Harper tried to help her. Rommie is suspicious. Trance examines Ler-Near, and says that the same procedure was done on him as on Bu-Habib. She says that parts of his brain were removed, specifically the parts associated with memory and cognitive ability. Rommie finds a coded transmission device in the room. They theorize that someone is trying to steal the scientists' minds.

The Collectors take Dylan to a cell, but he breaks free.

Rommie checks for links between Bu-Habib and Ler-Near, and discovers that, while they never met in person, they both worked on the study of the Engine of Creation. The missing Professor Wel-Dar, and one other scientist also worked on the Engine, and their knowledge and aptitudes match up with two other attendees: Kor-Kavo and Harper.

While searching for an escape route, Dylan finds Professor Wel-Dar in a cell. Wel-Dar is babbling about "ten radical isotopes" and the Abyss. Dylan jury-rigs a primitive transmitter in his cell, and continues to look for a way out.

Beka and Rhade begin to scan the old mining tunnels, looking for Dylan, and find his transmission.

The scientists at the conference are worried, and many start to leave. Harper stops them by challenging their courage, saying that great scientists need to be brave.

Dylan engages the Collectors in a firefight, but is pinned down, when Beka and Rhade come to the rescue.

At the conference, things are still falling apart, but Dylan believes that they can expose the killer with the information given by Wel-Dar. He tells Harper to ask the scientists about the "ten radical isotopes", so Harper makes a general announcement. When he does, Kor-Kavo's eyes glow red and her voice changes. She names ten unknown isotopes with negative atomic weights, which Harper notes is impossible. Kor-Kavo pulls out a device and points it at Harper. Rommie steps in the way before she can activate it, and Rommie collapses. Harper tries to shoot Kor-Kavo, but he has no power in his gun, and Rommie does not have enough power to stand. Harper gets Kor-Kavo's attention, and runs. He ducks into a lab where he can power up his gun, and shoots Kor-Kavo when she follows, to no effect. Dylan arrives at the last minute, and shoots Kor-Kavo with a plasma burst from his forcelance. This knocks her down, but she gets back up. She tells them that the Abyss has entered the world of matter, and will destroy everything. Dylan shoots her again, and she dissolves into a black puddle. Harper claims that he was never really fooled.

Dylan contacts Tri-Lorn, who claims that the debriefing summons was intended for after the conference, and blames tampering by the Collectors. Dylan observes that the Commonwealth has enemies within itself. Dylan also recommends Harper for a medal, and Tri-Lorn agrees.

When presenting Harper with his medal, they discuss the "radical isotopes". Harper reiterates that an isotope with a negative atomic weight is impossible, and theorizes that they must have something to do with the "other universe" of the Abyss, and may be the key to defeating the Abyss.