Louis Sacchetti is told by General Haast, the camp commandant, that he has been moved to Camp Archimedes to record what he sees. Dr. Aimée Busk, the camp psychiatrist, further explains that as those around him are dying of syphilis induced by the strain Pallidine (which kills in about nine months), they undergo stunning increases in intelligence, which the military hopes to employ.
In his diary, which forms the bulk of the narrative, Sacchetti reports meeting the other men at the camp. Among them is George Wagner, the first prisoner Sacchetti meets and the first he sees entombed. The prisoners’ leader is Mordecai Washington, who knew Sacchetti in his school days. Washington is deeply immersed in alchemical studies and has become a magnificent polymath in only a few months. The prisoners prepare a brilliant production of Christopher Marlowe’s Doctor Faustus, but Wagner dies before he can play the lead. Then Washington and Haast take part in an alchemical attempt to obtain immortality, but it goes wrong, and Washington dies horribly. The following night, Sacchetti dreams the truth, that he is infected and dying. The balance of his journal is in scraps, heavy with literary allusion, showing that he gets sicker and more brilliant each day.
Busk leaves the camp, and a new group of subjects arrives, centered on Skilliman, a failed but nasty and ambitious scientist who chooses the Pallidine treatment in order to develop weapons. Sacchetti sets up a museum of artifacts that add up to the fact that Busk, as a result of sexual intercourse with Washington, has spread the syphilis rapidly across the United States. Skilliman’s conflicts with Sacchetti, the only survivor of the original group, begin as Sacchetti starts to draw off Skilliman’s followers. A confrontation ensues in which Skilliman demands that Sacchetti, now blind, be executed. Instead, Haast kills Skilliman and reveals that the alchemical experiment was a disguised brain pattern exchange in which Washington’s mind came to occupy Haast’s body. The simultaneous reverse action of the “mind reciprocator” so horrified Haast that it was he who died in Washington’s body.
The novel closes on a challenge to the changed prisoners, who look forward to a future of both genius and eternal life, although that prolonged life would be at the repeated cost of the lives of others, until a vaccine is found for the Pallidine infection.