Claas lures Nora and Wibke to Captain Heintje Hansen's bachelor party at the "Zum alten Kutter" sailors' club with false promises. After 50 years of waiting, the old sea dog finally wants to marry his beloved Helga Wartberg. However, the celebration comes to an abrupt end when the bride-to-be abruptly breaks off the engagement in front of the assembled crew, and shortly afterward, nurse Muriel Schwarz is found dead. It quickly becomes clear: it was murder! Equally troubling: the balcony at the nursing home from which Muriel fell is right next to Rayk's father's room—and he has vanished without a trace since the crime.

The cruise ship "Edda," with a group of novice nuns on board, finds itself in distress when Captain Marten "Ahab" Drake falls overboard. Only a mysterious figure saves the ship at the last second from crashing into the quay wall. The nuns escape with nothing more than a scare, but Sister Renate is firmly convinced that the rescuer was sent in the form of Jesus Christ to save them. When Ahab is recovered from the water shortly afterward, however, it quickly becomes clear that purely earthly circumstances caused the captain's death. Detectives Nora and Jon investigate.