The married couple Frank and Yvonne Berthold are found murdered in a high-rise settlement in Bremen. Her nine-year-old daughter witnessed the crime without being noticed by the perpetrator. Therefore, she is in great danger of becoming the next victim. The child is severely traumatized and has not spoken a single word since she was found. Inga Lürsen is the only one who manages to gradually gain her trust. The child escapes from the hospital, back to the family's apartment, and doesn't want to leave there again at any price. Chief inspector Inga Lürsen, who knows that there is nowhere to give the child 100% protection as long as the perpetrator is at large, decides with a heavy heart to pretend to be the little one's aunt and to stay in the apartment with her.
The victim's work colleagues and their wives also live in the same house. Inga feels more and more clearly that something is wrong with them. Or does the murder have something to do with the victim's work in the port, as Stedefreund suspects...