Tom and Semir investigate the murder of Philipp, Anna Engelhardt's boyfriend, after she has disappeared and everything points to her as the culprit. While Inspector Schulte suspects the boss, the highway inspectors go to work behind his back. They discover that Anna is being held captive in a basement room by Philipp's daughter, Lisa. Lisa, who blames her mother for Philipp's separation, murdered him out of anger. Through clever investigations, Tom and Semir finally discover Lisa's motives and save Anna.