Christian Alvart's gripping thriller begins when the German police capture serial child killer Gabriel Engel literally red-handed. While he confesses to his crimes, there is the unsolved murder of a young girl in a remote Bavarian town that bears his hallmarks. The town's part-time police officer Michael Martens is invited to interrogate him but as the two face each other across the interview room, Engel begins to play mind-games with Martens, with certain information he has about the killing that may rock Martens' world.