Captain Elizabeth Lidiard escorts a university expedition to the planet Ardethe in search of ancient alien technology for use by their government, the Administration. Her party accidentally triggers a booby-trap upon discovering an ancient buried city, but as they proceed two of the party turn out to be traitors who slaughter the others. This is not Ardethe at all, but another planet to which the expedition was lured so the traitors could enter the buried city and find the man hidden there -- one Christopher Cwej, host of the Baygent Apotheosis. But there are other things in the city as well, and the killers are themselves killed...

Benny is preparing to go to Ardethe herself to find out the truth on behalf of Irving Braxiatel, when Jason Kane unexpectedly shows up and asks to come along. Benny, assuming that he's in it for the money, flatly refuses, so he steals the planet's location co-ordinates from her and sets off. At the last minute he is joined by Emile Mars-Smith, who acquired a taste for adventure while fighting the Sunless. Benny discovers what they've done too late -- and Jason has stolen the wrong data crystal from her, and is heading not for the real Ardethe but for the other world where the previous expedition was slaughtered. The mysterious Knights of Jeneve are somehow involved in the conspiracy to hide the truth about Ardethe, and Benny learns that Jason has been hired by them to investigate something called the "Baygent Apotheosis". He agreed because it somehow involved Chris Cwej, and he wanted to protect Benny from getting involved; but if Benny's and Irving's suspicions are true, Jason and Emile may very well be going to their deaths...

A prison ship, the Kaybee 2, is diverted to salvage what remains of the previous expedition -- but the ship's computer, BABE, knows more than she's saying about what's going on. The ship's prisoners are all female, and Lloyd, the "Top Dog" amongst the prisoners, selects an away team while facing the bullying Townsend's attempts to undermine her authority.

Governor Tollund's only interests lie in his own comfort on the ship and his constant attempts to assert his authority over his rebellious prisoners. There are two security guards on the ship, both dog-like Grutchas, but only Cassius is on active duty as Brutus has fallen ill and is being tended by Dr Njobe.

Jason's skimmer nearly collides with the Kaybee 2, but he manages to land more or less safely on the planet. He and Emile hide and watch as Lloyd's team explores the planet and finds the entrance to the city. As soon as the hatch is opened, Jason starts to pick up a distress signal from within. He and Emile sneak into the city behind Lloyd's team to follow the call to its source, and on the way Jason recognizes the city as a replica of Emmanual College in Cambridge. The prisoners, meanwhile, find the bodies of the previous expedition, and Townsend panics and demands that they turn back. Lloyd refuses, as their parole depends upon the success of this mission. They split up to explore the city and search for salvageable material, but Christine Connor soon determines that there is no metal in the city -- it's as if the little they found was put there to lure them further in. Townsend, on her own, sees two shapeless forms flitting through the air towards Grierson and Hallett, and hears a brief, distant scream...

Jason and Emile find the source of the signal -- the unconscious Chris -- and are captured by Lloyd and Connor. Chris recovers temporarily and claims that this is a trap, but discovers that he's suffering from near-total amnesia and can't explain any further. Lloyd decides to return to the ship with her captives, but Townsend panics and must be subdued when she tries to kill Lloyd, claiming that something is trying to kill them all. As the team departs, BABE shuts down the city -- its purpose has been achieved and the Baygent Apotheosis is at hand...

Chris drifts in and out of consciousness, and dreams about fighting a dragon; although he vanquishes it, something much darker and deadlier bursts out of its body. The ship unexpectedly leaves orbit on BABE's orders; she and Dr Njobe are working together and blackmailing Cassius into submission by using the ill Brutus as a hostage. While Grierson is alone with Connor and Hallett, her head unexpectedly explodes and Connor and Hallett fall into unexplained comas. As Chris recovers he overhears BABE, Njobe and Cassius discussing the plot, and warns the others. The prisoner Ghoti Ramanee breaks into Cassius' quarters and hacks into his computer, but before she can learn anything Dr Njobe finds and kills her. Njobe blames Cassius for nearly ruining the plan and kills Brutus, and while Cassius is still in shock transfers a "Jithii" from Connor's head into Cassius'...

The others go to the medical bay to confront Dr Njobe, but Hallett awakens and the Jithii in her head transfers to Townsend -- causing Hallett's head to explode in the process. The survivors take shelter in Tollund's office, as Chris' memories start to return; the Jithii are artificial life forms programmed to hunt for something, but they are still searching for suitable hosts. Tollund forces them out of his office, still trying to pretend that everything is under control, but Townsend later finds and kills him.

Chris and Lloyd confront Dr Njobe, who explains that the Jithii are searching for descendents of Baygent, the man who founded the Knights of Jeneve. They have kept Baygent's memories alive through encoded DNA patterns; once they have a suitable host they will effectively be able to bring Baygent back to life, to put him on the throne of the Earth Empire. Despite a near-perfect DNA Match, Chris proved to be an unsuitable candidate due to his body bepple and latent psi powers, so when the Knights found him they wiped his memories, uploaded the control codes for the Jithii into his mind, and left him on the false Ardethe to wait until the Jithii had fully gestated. The Jithii accidentally killed the first team they sent to collect them, but the Knights had already infiltrated the Kaybee 2 as a backup plan.

Townsend arrives, possessed by her Jithii, and in the battle which follows Njobe is seriously injured. Cassius hunts the others to the shuttle bay, where they are trying to escape, but with Emile's help they expel him into space, killing him and his Jithii. Njobe orders BABE to self-destruct in order to hide the evidence of the Knights' crimes, and then confronts Jason, who kills her and deactivates BABE. Chris confronts Townsend, who attempts to pass the Jithii into his mind -- but the psi powers which enabled Chris to retain his memories through the Knights' attempted mind-wipe also enable him to eject the Jithii from his mind. It retreats back into Townsend's body, and Chris shoots and kills both her and the Jithii.