The film begins with a British commando raid whose aim is to assassinate Rommel. It fails. The story is narrated by actor Michael Rennie, who dubs the voice of then-Colonel Desmond Young, who plays himself in the film. Young is captured and meets Rommel briefly as a prisoner of war; he makes it his mission after the war to discover what really happened to Rommel during the final years of his life — at the time that Young wrote his book, it was believed that Rommel had died as a result of the wounds he had suffered when an Allied fighter strafed his staff car.
The Germans are defeated at El Alamein in 1942. The situation is made worse when Rommel is ordered by Adolf Hitler (Luther Adler) to stand fast and not retreat, even in the face of overwhelming Allied superiority in men and materiel. An ailing Rommel is sent back to Germany to recuperate while his beloved Afrika Korps is driven back across North Africa. Rommel becomes increasingly disillusioned with Hitler after his pleas to evacuate his men are dismissed.
Rommel is approached by an old family friend, Dr. Karl Strollin (Cedric Hardwicke), to join a group plotting to overthrow Hitler. Rommel is very hesitant and finally insists on meeting Hitler personally in an effort to persuade him to see reason. Hitler does not heed Rommel's gloomy predictions about the war, screaming that wonder weapons in development will turn the tide.
Rommel is placed in charge of defending the Atlantic Wall against the anticipated Allied invasion. When the Allies land in France on June 6, 1944, he and his superior, Field Marshal Gerd von Rundstedt (Leo G. Carroll), are handicapped by Hitler's belief that it is a diversion, with the real invasion to come at the Strait of Dover. As a result, they are denied urgently-needed reinforcements, allowing the Allies to secure a beachhead. This is the final straw. Rommel joins the conspiracy. However, when he tries to recruit von Rundstedt, the latter excuses himself by stating he is too old for such things, but wishes Rommel well