Nick Baumgarten, deputy chief of CID in the Aargau cantonal police, faces a huge challenge: the CEO of the local casino was stabbed to death, and there are absolutely no leads. Neither the dead man's wife nor his best friend have any idea where to look for the killer. It is only when the body of a woman is found in the Beznau weir that connections start to appear. In what way is the attractive psychiatrist involved? And why does the personnel manager of the casino tell the police only part of the truth? The crucial lead is finally provided by Marina Manz, owner of the best beauty salon in Aarau and Nick Baumgarten's girlfriend.