Hubert and Staller witness a gas station robbery. The robber manages to escape, but the case seems to be quickly solved: The DNA traces at the crime scene belong to Heiko Martens. There's just one problem: The man is dead! Martens was reported missing after a boating accident and was only recently officially declared deceased. His grieving widow, Sabine Jäger-Martens, clings to the hope that her husband might still be alive. The deceased's sister, Roswitha Martens, has a theory of her own: her sister-in-law Sabine wanted to kill Heiko—who was deep in debt—on the boat back then to collect his life insurance, but her attempt failed.