The Gutenberg Bible is the world's first book made on a printing press, everyone knows about it. But hardly anyone knows that another book was also printed there, in the Guttenberg workshop, the very fact of whose existence the church prefers to hush up, and its surviving copies are confiscated and set on fire... It all started with the fact that Nick Ash, an FBI employee, a strange message arrived from a mountain village in Germany - an image of a medieval playing card and two lines with incomprehensible text. At the same time, he learns that unknown people have kidnapped Gillian, the woman with whom Nick is in love. Ash stops what he's doing and goes in search of Gillian. And soon he turns from a hunter of criminals into an outcast and a fugitive, because the riddle to which Gillian found the answer is one of those that it is better for a mere mortal not to know at all.