Young an civil captain Hellmut Kehding has to bring the "Wilhelm Gustloff" with about 1500 members of the Wehrmacht and almost 9000 refugess savely to Kiel. The story begins three days before the catastrophe in Gotenhafen. Among the refugees is Lilli Simoneit, whose little daughter did not survive the exertions of the flight and whose son Kalli is in danger of being drafted. Moreover Lilli takes care of pregnant Marianne. They hope to get into safety.
In Gotenhafen Hellmut Kehding meets his former love Erika Galetschky, who workes for the marine. He wants her to go with him on the ship, but her cousin Hagen Koch, who is the spark on the "Gustloff" wants her to stay.
Hellmut Kehding is not the only one on board who has a say. Lieutenant commander Petri, the military transport leader, is against the refugees on the ship. He wants the "Gustloff" to cast off early, to bring his submarine soldiers to their deployment in Kiel. The old captain Johannsen is not able to decide anything and only wants to save himself and the NSDAP deputy Escher is just interested in celebrating the day of the takeover of power. The only one who shares Hellmut's sorrows about the ship and the refugees is lieutenant commander Leonberg who is worried because he cannot provide an escort to secure the journey.
A surprise for Hellmut is that his brother Harald, with whom he had a fight for years, is on the ship, too. Harald works for the prevention of sabotage and has some mysterious tasks to do in Gotenhafen.
As the preparations for the cast off are running, the refugees come on bord. Among them Lilli and her son, Marianne and Erika. When the ship puts to sea it receives a strangly enciphered radiogram and the journey is stopped. Harald fears an attack and the whole ship is searched. Erika gets under suspicion as she is illegal on board. Meanwhile everyone is searching her, she tries to reach Hellmut on the command bridge. When there is a second radiogram the situation gets out of control. Lieutenant commander Petri sets the position lights, as there is the assumption that a fleet of minesweepers is on collision course. Hellmut doubts this and is deprived of the command. A Russiam submarine already has detected the position lights and the "Gustloff" is shot with three torpedos and sinks within one hour.