Based on

Movies like The Last U-Boat (1993)

Near the end of WWII a lone U-Boat is sent from Germany to Japan carrying plutonium needed for a Japanese A-Bomb. During the long journey, news arrives on the radio that Hitler killed himself and Germany has surrendered. This causes a rift in the crew, the Nazi Party members wanting to continue to Japan since they are still at war, while the others just want to surrender or return home.