In the fictional town of Endwarden, pensioner Fintzel wants to renovate his attic. He finds a suitcase that belonged to his brother who died in World War II.
A dead person is found in the port of Duisburg. It is the inland boatman Heinz Petschek. He was stabbed. The skipper Jan Poppinga turns out to be urgently suspect; Petschek had a relationship with his wife.