After the savage murder of a little girl in his rural hometown, police officer Martens travels to Berlin in order to get a confession from incarcerated serial killer Gabriel Engel. But Engel, who was arrested by seasoned detective Seiler, tricks the provincial cop into a nerve-wrecking mind game about deception, truth, good and evil. Soon it becomes clear, that the clues point in another, unexpected direction and that the real killer is still on the loose.