Two reporters watch as pilot Johnny Stevens takes off in a new plane built for the military. They then demand to see businessman Samuel Thornton, whose office is at the air field, and insist on knowing if there is a connection between the one million dollar reward he once offered for the capture of Nazi commander Adolf Hitler, and the one million dollars worth of planes he has donated to the Army. Thornton relates to them his story: Before America's entrance into the war, Thornton publicly offers a one million dollar reward to anyone who can capture Hitler, dead or alive, with the hope of avenging the death of his brother, an exchange professor who was killed by the Gestapo. Gangster Steve Maschik, recently released from prison, and his cohorts, thug Hans "Dutch" Havermann, and lawyer Joe "The Book" Conway, announce themselves at Thornton's office to accept the challenge. Thornton doubts Steve's qualifications, but Steve considers Hitler a mobster and as a former underworld czar, feels eminently qualified for the assignment. Joe approves the contract and Thornton signs them up, promising to erect a suitable monument to them if they should not return. Steve, Joe and Hans leave immediately for Canada, where they enlist with the Royal Canadian Air Force. They are sent to England, and, one day while their paratroop practices maneuvers, they eject their instructor and hijack the plane. Pilot Johnny Stevens is forced to fly them within 250 miles of Berlin, where they crash land. With Johnny as an unwilling accomplice, the men hijack a Nazi transport truck, and after they are stopped by S.S. officers, they are escorted to Dachau, a concentration camp. Colonel Hecht, the camp commander, interrogates Steve, who slyly tells him that he and his friends are on a special commission for Hitler and have just returned from England with information. Hecht imprisons the Americans while he determines the veracity of their statements. Hecht confides his uncertainty to his girl friend, dancer Elsa, who, unknown to him, is the renowned "Rosebud" of the resistance underground. Elsa arranges for Steve, Johnny, Hans and Joe to escape in the car in which she is riding, but Hans is killed by the Nazis. Elsa leaves the men on a country lane, where they are picked up by a member of the underground and taken to a hideout in Elsa's home. Elsa returns home after making Hecht believe she was kidnapped and released, and Steve admits to her his plans to kill Hitler. Hecht soon learns that the Americans are a trio determined to kill Hitler. Although Elsa believes that Hitler's compatriots would continue on without him, she pledges her support to Steve, until she learns that Hitler has ordered the death of all the local villagers if the Americans are not brought forward. Hitler's coldblooded commandment only reinforces Steve's desire to kill him, and Steve is no longer involved in the plot for mercenary reasons, but has become a patriot. When Hitler arrives for a rest at his nearby castle, Elsa is called upon to dance for him, and despite her protests, Steve, Johnny and Joe impersonate her musicians. They are unable to play a note of music, however, and after shooting several officers, manage to capture Hitler. Steve sends Johnny and Elsa to fly to England in Hitler's private plane and apprise the English of the situation. Steve takes Hitler, who has turned into a sniveling coward, back to the hideout. Based on the testimony of Meyer, a doctor who years earlier saved Hitler's life, Steve verifies Hitler's identity by shaving his moustache to reveal a scar on his upper lip. Shortly after, S.S. officers break into the house and capture them all, but Hecht does not recognize Hitler without his moustache, and shoots him. Steve, Meyer and Elsa's friend, Greta, are later executed as the village burns. Thornton finishes his tale, and states to the reporters that the plane is only the beginning of his promised reward. Thornton now recognizes that it was wrong to go after Hitler, who he realizes was just a figurehead, and that they must go after all those who represent his warped ideals.