Maximilian Rapp confesses to 23 murders. But the BKA investigator Tara Schöll has doubts about the guilt of the convict. The highly sensitive man was arrested too easily and the young policewoman sees too many discrepancies in various details. In fact, there is evidence that Rapp cannot have committed all the murders. Does he even sit in jail as an innocent person while the murderer or murderers are still at large? Tara and partner Henry Kloss now have to capture the real perpetrators in the highest degree of secrecy, while Rapp supports them with his knowledge of the murders and his excellent senses. But is it really just his high sensitivity and his previous work in the evidence room that allow Rapp to provide decisive clues? Or is he a dangerous murderer after all?