In 1942, both Nazi Germany and the Soviet Union are gathering forces and supplies in one particular sector of the Eastern Front for a major attack.

In an attempt to find out where the Germans plan to strike, Colonel Semenov (George Macready) has a small paratrooper unit dropped behind enemy lines to attack a divisional headquarters and hopefully take an officer prisoner for interrogation.

The local partisans, led by the wily Kostyuk (Roman Bohnen), provide a guide, Lisa Elenko (Marguerite Chapman).

Then, just as Elenko brings him a message, German artillery hits the building, causing part of it to collapse.

Though the prisoners rank no higher than a sergeant, he is convinced one of them is an officer in disguise, based on a monogrammed pistol and a monocle he has found.

He begins questioning the men one by one, but while he rules out ex-miner Stillman (Rudolph Anders) and a former magician (Philip Van Zandt), he cannot pinpoint his man.

Von Sturmer taunts him, revealing the truth about the German attack and boasting about his earlier lie.

As the Cold War developed, the fact that the Soviet Union was depicted sympathetically in the film began to be seen as inappropriate and suspicious.

Moreover, the three principal writers (Lawson and the Stevensons), one actor (Parks), and the production supervisor Sidney Buchman were all blacklisted due to suspected Communist affiliations.