It is the final tragedy of WWII. On May 3, 1945, British fighter-bombers attack a collection of ships in the Baltic Sea, which they mix up with German warships. A terrible mistake. Three ships on which the SS had taken almost 10,000 prisoners from the Neuengamme concentration camp also anchored in the Bay of Lübeck just outside Neustadt. As people wait to be rescued, the former luxury liner Cap Arcona explodes in a massive fireball. Almost everyone dies. But was it really the British, as everyone thought? The SS had turned Cap Arcona into a floating bomb. But who fired the detonator? A mystery that remains unsolved to this day...