On a stormy Chicago night, renowned semiotician Dr. Evan Wilding and his brother, River, who's back from an archaeological dig, reunite in a mystery. A package addressed to both of them contains a hand-drawn maze, an ancient Cretan coin, and a cryptic greeting: Let the game begin.

The opening move is murder.

In a downtown alley, a man has been found nearly cleaved in two, a symbol drawn on his forehead and a savage rip in his throat. Given the clues, Evan sees a parallel to a fearsome Greek myth. Which means his friend Detective Addie Bisset is on the trail of a legendary flesh-eating monster--one terrifyingly human and tumbling a panicked city toward chaos.

Evan, Addie, and River scramble to discover who's behind the appalling crimes and decipher the baffling motives. The body count is rising. The endgame is nowhere in sight. And the stakes are nothing less than life and death.