Professor Hans Rekke and Micaela Vargas have earned a reputation for solving the unsolvable. But they've never been confronted by a serial killer. That changes when Rekke receives a visit from Spanish chief inspector Rafael Corales, who is unable to forget the unsolved murder of a young woman in Santander in 1988.

Now other bodies have come to light, marked with signs that seem to be some kind of numerical order. Still recovering from his latest hypomanic episode - his relationship with Vargas strained by a secret she's keeping - Rekke agrees to help track down the killer. Clues from a posthumously published short story the victim draw him undercover into the murky world of Sweden's literary scene - authors, agents and producers who are past masters at selling a lie.

To unmask the killer, Rekke must relearn the difference between fact and fiction, and discover what really happened that night in Santander in 1988.