The corpse of a woman with a mysterious symbol carved into her chest by the killer was discovered in Bern. However, this is not his only victim. Dutch profiler Maarten S. Sneijder and BKA Commissioner Sabine Nemez are hunting for the criminal, but it seems that the killer is always one step ahead. Meanwhile, a young specialist in psychology, Hannah, arrives at Steinfels, a prison for criminals with mental disabilities. She should be doing group therapy sessions. But she is interested in one and only prisoner - Piet van Loon. Sneijder once put him behind bars. So both experienced investigators and a novice psychologist found themselves drawn into a diabolical game in which there will be no winner.