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.
Humphrey Bogart heads a decent cast in this exciting compendium of tales of maritime courage and determination during WWII. Initially he serves under Raymond Massey ("Capt. Jarvis") on a tanker but when that falls foul of an U-boat, they find themselves stranded on a raft and left to the elements by it's particularly unpleasant Captain. Some while later, the team reunite to escort a convoy to Murmansk and encounter the same submarine and a deadly cat-and-mouse game ensues. It is bit too long, but Massey, Bogart alongside the always reliable Alan Hale manage to bang the drum successfully for the most part, demonstrating the prowess of these brave sailors facing the elements and Nazis as they tried to keep the supply lines open. The cinematography is tautly presented and effective, as are the effects and the flag-waving is a bit more sophisticated than in many similar propaganda exercises - tragedy and success occur giving the film a certain degree of realism and plausibility.