In occupied Berlin, a US Army Captain is torn between an ex-Nazi cafe singer and the US Congresswoman investigating her.

Sergeant Joe Gunn and his tank crew pick up five British soldiers, a Frenchman and a Sudanese man with an Italian prisoner crossing the Libyan Desert to rejoin their command after the fall of Tobruk. Tambul, the Sudanese leads them to an abandoned desert fortress where they hope to find water. Soon a detachment of German soldiers arrives and attempts to barter food for water, but Gunn and his followers refuse. When the Germans attack, Gunn leads his desert-weary men in a desperate battle, hoping that British reinforcements can arrive in time.

Merle Oberon plays a Norwegian resistance figure in a small town, married to a Nazi commandant. When his superiors begin to suspect her, the Allies land an assassin to kill him -- an assassin who happens to be her former lover.

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.

Somewhere in Europe, in a city occupied by the Nazis, a gentle school teacher finds himself torn between collaboration and resistance, cowardice and courage.

Hans Memling, a young intellectual, patriotic German, is secretly opposed to the Nazi regime. With the aid of Gustav Schultz, Father Pommer, Anna Wahl and others, he is gleaning accurate information from foreign radio broadcasts and distributing it through Germany with an underground-press operation.

A tugboat captain serves under his rival as a U-boat chaser in World War I.