A policewoman from Berlin who testified against an Arab clan boss is starting a new life in Passau with her daughter under a new identity and with the support of witness protection. The policewoman, who until recently was a group leader in the Mobile Task Force (MEK), now calls herself Frederike Bader, her daughter Mia Bader. In Passau, she meets private detective Ferdinand Zankl. In a supermarket, she rescues him from a violent confrontation with a shoplifter.

Private detective Ferdinand Zankl is arrested by the Passau police on suspicion of murder. He is suspected of having killed his ex-girlfriend, an animal shelter manager.

A man in search of his son: Adil Bahdari comes from Berlin to Passau after a fisherman finds an expensive watch with a dedication on the back on the banks of the Danube. The watch was a gift from Adil Bahdari to his son Ahmed, whom he has not heard from for some time. He hires private detective Ferdinand Zankl to search for his son.

Frederike Bader, a former policewoman from Berlin, currently living in witness protection in Passau, is supposed to help her ex-boss Jochen Mohn - formerly a witness protector, now head of the Passau CID - in a private matter.