Bernice's new friend Maeve Ruthven, professor of comparative religions at St Oscar's and a devout Marunianist, invites Benny on a sea cruise. The religious orders of the hermaphroditic Saraani have been exiled from their homeworld following an atheist revolution, and the authorities on Dellah have agreed to let them settle on one of the unoccupied islands in the Silvasic Sea. The Saraani have booked the Lady of Lorelei for the journey, but for most of the pilgrimage they will confine themselves to their own separate area of the ship. Benny will thus have the run of the luxury accomodations, and she leaps at the chance of a holiday.

Arriving on the ship with seconds to spare, Benny is shocked when her alcohol is confiscated per the Saraani's instructions. Maeve is also shocked by the presence of her ex-husband, Brion Arvaile. She and the other academics on the journey have come to learn about the Saraani's religion and psychology, but Brion is a genetic engineer; this is why he and Maeve split up, as she couldn't reconcile his work with her religious convictions. The Saraani are a private people -- why has he been allowed on board?

Benny meets a Saraani named Vilbian, who has stolen her alcohol from the stores despite his religion's prohibition; she promises not to turn him in if he shares it with her, but he doesn't explain why he's turned to drink. The ship arrives near an island which appears perfect for the Saraani's purposes, but the Khuylan, the pilgrimage's religious leader, seems to be trying to prolong the pilgrimage for some reason. While sunbathing on the island, Benny is attacked by a military bioconstruct which calls her by name, seriously injures her, and then flees back into the sea for no apparent reason. While Benny recovers in sickbay, Arvaile explains to her, Maeve and the captain that the bioconstruct appeared to be from his homeworld Vishpok. Arvaile had claimed to have fled his homeworld's repressive government, but he now informs the others that he is in fact a member of the Resistance which recently overthrew that government -- and it appears that the former Czaritza, Violaine, has sent an assassin to kill him in revenge.

Maeve believes that Brion is lying and follows him to the ship's hold, where she finds dozens of bioconstructs in cryogenic storage. Before Brion can explain what they're doing there, the one which attacked Benny comes back to life and kills Maeve. Benny, who has realized that the bioconstruct appears to have the mind of a student who disappeared from St Oscar's some time ago, emerges from sickbay to find Brion and Vilbian standing over Maeve's body, with Vilbian sticking an organic protrusion of some kind from his mouth into Maeve's. Brion pushes her away, and by the time she gets back, Brion and Vilbian are gone and Maeve is dead.

Vilbian later contacts Benny and explains that he was conducting a ritual known as Holy Transference -- and she's startled to learn that it involves transferring a dying mind into a Saraani host for later reincarnation in a newborn Saraani. Maeve's mind may still be alive somewhere inside Vilbian. The Khuylan demands that the alien mind be exorcised from Vilbian's, but Benny convinces Captain Fontana to use his authority to prevent this; if Vilbian can commune with Maeve's mind he can find out who or what really killed her. Meanwhile, the Saraani discover that they have all been sterilised by a drug in their water supply and suspect that one amongst them is a Renaissant traitor.

The Saraani Mirrium, worried by Vilbian's apparently heretical actions, contacts him and discovers him using human communications technology. Vilbian refuses to explain himself, only telling Mirrium to tell Benny to look in B-Hold for answers. Mirrium passes on the message to her, while Vilbian goes to B-Hold, transfers Maeve's mind into one of the bioconstructs and orders it to download its programming information. Benny and Fontana arrive and catch him, but when Fontana pulls a gun on Vilbian this triggers the active bioconstruct and it attacks him. The weapons activity triggers Maeve's bioconstruct, and she nearly descends into madness when the wetware takes control and forces her to kill the other bioconstruct. As Maeve flees in shock, Brion and the Khuylan arrive -- and to Brion's and Benny's horror, the Khuylan kills Captain Fontana and prepares to kill Benny as well.

Brion saves Benny by claiming that she's his wife, and privately explains the truth to her; he's not a Resistance member at all but a covert agent for Czaritza Violaine, and the Khuylan has agreed to serve Violaine in return for help to conquer Saraanis and expel the Renaissants who took control from the religious orders. In fact Brion has realized Violaine intends to take control of Saraanis herself; Dellah has taught him that there can be a better way of life than Violaine has shown, and although he initially married Maeve as a cover he had truly fallen in love with her. He thus convinced Vilbian to conduct Transference on her in the hope of bringing her back to life. But Violaine is on her way...

A Vishpok battleship lands on Dellah and Vishpoi soldiers seize control of the Lady of Lorelei. The confused Saraani are herded over to the ship, along with Vilbian, who admits to Mirrium that he was working on behalf of Earth authorities to prove that the Khuylan had allied himself with Violaine, and had begun drinking to blur his confusion over his clashing responsibilities. Brion and Benny are taken to the cruiser as well, where Benny learns the rest of the plan; the Saraani are to become slaves, used to transfer loyal Vishpoi soldiers' minds into bioconstructs and provide Violaine with an invincible army. The Khuylan sterilised the other Saraani so they could perform Holy Transference on the soldiers without automatically giving birth to new Saraani with the soldiers' memories, and Brion kidnapped Benny's student in order to test the process before Violaine arrived. One of the Saraani turns out to be a Renaissant who had joined the expedition to investigate rumours of a conspiracy to conquer Saraanis; the Khuylan uses him as a scapegoat for the sterilisations and executes him, and the horrified Mirrium realizes that Vilbian has been telling the truth.

Maeve, trying to keep control while her bioconstruct's wetware urges her to kill, hides with the rest of the bioconstructs and is shuttled over to the Vishpoi ship with the others. There, Brion finally snaps and speaks out against Violaine, who orders her guards to kill both him and Benny. Maeve, trying to help them, loses control of the wetware and her bioconstruct body goes on a rampage, killing everyone it encounters -- including Brion. Benny helps the Saraani to escape, but the Khuylan dies. Mirrium, who has learned to reconcile his religious beliefs with the shock of learning that the Khuylan betrayed them all, helps to calm the other Saraani, and thus becomes their new Khuylan.