Princeton. Good Friday, 1999. On the eve of graduation, two students are a hairsbreadth from solving the mysteries of the Hypnerotomachia Poliphili. Famous for its hypnotic power over those who study it, the 500-year-old Hypnerotomachia may finally reveal its secrets to Tom Sullivan, whose father was obsessed with the book, and Paul Harris, whose future depends on it. As the deadline looms, research has stalled, until an ancient diary surfaces. What Tom and Paul discover inside shocks even them: proof that the location of a hidden crypt has been ciphered within the pages of the obscure Renaissance text.

Armed with this final clue, the two friends delve into the bizarre world of the Hypnerotomachia, a world of forgotten erudition, strange sexual appetites, and terrible violence. But just as they begin to realize the magnitude of their discovery, Princeton's snowy campus is rocked: a longtime student of the book is murdered, shot dead in the hushed halls of the history department.