Dumarest delivers the message to Lemain’s brother Quendis on Loame and discovers that the primitive agricultural planet is an occupied tributary of Technos.  Technos has infested Loame with the “thorge”, a parasitic bio-engineered weed, to blackmail Loame into paying “tribute”: thousands of young men and women who are taken to Technos, and whose ultimate fate is unknown on Loame.  Lemain had been secretly searching off-world for a way to stop the thorge, but the message informs Quendis that he failed. Quendis reveals that Delmayer’s farm was financially (and physically) destroyed by the thorge. Delmayer committed suicide but his daughter Elaine had a photographic memory and might remember something of interest.  Unfortunately, Elaine left Loame to pursue education and a career on Technos many years before Technos embarked on their current course of expansionism.

Dumarest sneaks into the next batch of tribute and is transported to Technos.  He escapes and learns that Technos is a high-tech meritocracy based on educational achievement, and that the population appears to be largely ignorant of the government’s recent imperialist endeavors. While on the run, he has a chance meeting with Mada Grist, a member of the planetary government who appears not to be a native of Technos, but a very young woman from Loame.  His conclusions don’t shock him at all.

Dumarest contacts Elaine Delmayer, whose photographic memory has allowed her significant advancement within the medical establishment on Technos despite being an off-worlder.  However, she has no reason to trust him and attempts to turn him in to the authorities.  Mada, who has had him followed since their first encounter, aids his escape.  Mada appears to be more under the influence of her hormones than would be befitting a woman of her position, and seduces him.  She then asks him to assassinate the Technarch, the once titular head of state who now has ambitions of dictatorship and may be going insane.  Dumarest refuses, and is finally re-captured not long afterwards. In the process of his escape attempt, capture and interrogation, Dumarest learns that the aging Technarch is indeed going insane, but that the Cyclan is behind Technos’ recent aggressive posture toward her neighboring worlds.  However, the Technarch’s growing paranoia has made him distrustful of his advisor Cyber Ruen, and he refuses to turn the prisoner over to the Cyclan.

Instead, Dumarest is to be fully healed (having been tortured, naturally) and prepared for a special experiment.  Who better than top-gun surgeon Elaine Delmayer?  Dumarest confronts her and she admits that the tribute is used to fill menial jobs at which the highly educated citizens of Technos chafe, and confirms that those from Loame have a genetic makeup that makes them particularly good cell donors for growing tissue and organ replacements.  However, she is reluctant to believe his story that they are being used to provide whole new, young bodies for the aged rich and powerful (like Mada Grist).  He eventually convinces her, but although she offers to help him escape he instead sends her to summon the civil authorities and put an end to the conspiracy, hopefully in time to save his life.

The Technarch desperately wants a new body, but is unwilling to risk the 20% mortality rate. Body replacement pioneer Yendhal theorizes that survival is an attribute not of the mind or the body, but of the very genetic structure of the subject.  Yendhal has concocted an elaborate maze with all manner of mental and physical hazards which can supposedly only be avoided by reactions made at a sub-instinctive level. Anyone who survives the test must possess the genetic survival trait, and will therefore be a perfect body donor for the Technarch.  The only problem is, no previous subject has lasted more than a few minutes.  Oh yeah, if you’ve ever read a Dumarest book, you know he’s gonna end up in there…

Of course, if you’ve ever read a Dumarest book, you know that Earl is “survival trait” personified, so naturally he makes it through the experiment alive.  In the meantime, however, Cyber Ruen has discovered what is going on, and if a Cyber could feel any emotion he would be panicking because he has been instructed to capture Dumarest unharmed (for his knowledge of the affinity twin).  The Technarch refuses to end the experiment, so Ruen kills him and forces Yendhal to release Dumarest.  Dumarest kills Ruen to avoid being taken prisoner of the Cyclan, and then forces Yendhal into the maze in a nice bit of poetic justice before Elaine arrives with the cavalry.  The interim government agrees to kill the thorge on Loame and make amends with Technos’ neighbors, and Earl is ready to resume his quest.