Based on actual events, this is the story of a stranger who disrupts life in Sparta, a small and depressed town in upstate New York. Dean Lily, the "illusionist" of the title, in his early twenties, does magic tricks with playing cards, makes the young women of the town fall in love with him, and is really Lily Dean--a woman. Chrissie Peck, the story’s survivor, who leaves town for college at the end of the novel, befriends Dean and watches as he seduces the single mother Terry Kluge, and then abandons her for the more conventionally attractive Melanie Saluggio.

To each woman, Dean is the perfect man--gentle, funny, caring--and, in Terry’s case, the source of profound sexual pleasure. But Dean is arrested after stealing from Terry, and a newspaper report reveals that he has the body of a woman, that what he calls his "deformities" are in fact breasts.

The abused and sociopathic Brian Perez, who has always loved Melanie, accosts them and forces Dean to expose his body to her. After Melanie has left, appalled, Brian rapes Dean, who is persuaded in hospital to tell the police. Dean returns to Terry, who realizes that her love for Dean exceeds both his gender and his betrayal of her, but Brian tracks them down and murders Dean, Terry, and Terry’s small son.