Bente, a school dropout, was a foster child on the Strand family's remote farm. Forensic medicine finds a key in Bente's stomach. Where was the girl going with two cans of gasoline? Why did the local gas station attendant sell her gasoline even though it was known that she was an arsonist? Which lock does this key fit into? Local policeman Lars Klapproth might be able to contribute to solving the case, but he does not. Because Lars is the father of Maria's missing daughter Matilde. He had made the toddler disappear with the help of GDR state agencies during the reunification period. When Maria, who had fled the republic, returned to get her daughter shortly after the fall of the Berlin Wall, Matilde had already been adopted and could not be found.