A US freighter is torpedoed by a Nazi submarine while en route with vital supplies to Russian allies. The captain and his first mate manage to rally the survivors and return home to a hero's welcome. After a short period of leave, the spirited crew is assigned a new ship - and another chance to carry out the mission. Second World War adventure, with Humphrey Bogart, Raymond Massey, Alan Hale, Julie Bishop and Ruth Gordon.

Merchant Marine sailors Joe Rossi (Humphrey Bogart) and Steve Jarvis (Raymond Massey) are charged with getting a supply vessel to Russian allies as part of a sea convoy. When the group of ships comes under attack from a German U-boat, Rossi and Jarvis navigate through dangerous waters to evade Nazi naval forces. Though their mission across the Atlantic is extremely treacherous, they are motivated by the opportunity to strike back at the Germans, who sank one of their earlier ships.