In the fall of 1944, German officer Hans Von Kroner is infiltrated among Allied POWs in a POW camp in order to spy on them and report their escape plans to the camp commandant. Hans Von Kroner easily passes himself off as an American POW due to the fact he grew up in the U.S. Due to his efforts, several escape attempts are discovered and thwarted. Later, during the last major German offensive of the war in the Ardennes region of Belgium, Hans Von Kroner's skills are sought again by the German headquarters. He is ordered to take command of a group of English-speaking Germans and infiltrate the American Army units fighting in the Ardennes. Posing as American G.I.s, Hans Von Kroner and his men are ordered to create panic and confusion among the retreating American units, to deliver fake H.Q. orders to various American commanders in the field and to commit acts of sabotage against the American forces. These actions are to last from the start of the Battle of the Bulge in mid-December until the day when the German armies reach their final objective at the port of Antwerp. After a rough start, Hans Von Kroner's squad manages to infiltrate the nearest American unit and begins executing its plans. However, Hans Von Kroner, who masquerades as American Sgt. Leonard Richardson, is worried that he and his men will be unmasked and shot as spies.