When Schimanski comes home from work in the evening, a girl is sitting on the stairs with him. It is 17-year-old Katja. Her mother, manager of the specialty restaurant "Hawaii", has been murdered, murdered in a way that suggests the perpetrator's very personal motives. Schimanski and Thanner inevitably have to look after Katja: someone is after her, looking for something that was not found in her murdered mother's apartment. It's about drugs. The major dealer and suspected murderer of Katja's mother is Straub, owner of the restaurant "Hawaii". They'll catch him - it's only a matter of time. But then it turns out that things are much more complicated. The police now urgently need Katja's help.