On the point of being arrested by the Gestapo, Nazi General von Hartmann, secretly working for the German resistance, asks American O.S.S. man Larry Brennan to hide his priceless family jewels at a convent in the Czechoslovakian town of Pilsen. Von Hartmann sends his daughter, Hedi, to guide Brennan to Pilsen. Unable to avoid capture any longer, the general commits suicide. After the war, Larry, now a wireless operator, finds himself in Germany again when his ship docks in Hamburg. Rudi Siebert, General von Hartmann's wartime aide, persuades Larry to undertake the recovery of the gems, now behind the Iron Curtain. Hedi has become a prostitute; she believes that Larry stole the jewels. Larry and Siebert persuade her to join them on the mission. They reach Pilsen using false passports and a stolen auto transport, but they discover that the convent has been converted into a police barracks. They break into the barracks at night, recover the strongbox, and return to West Germany. Larry and Hedi fall in love; later, the two discover that they have been doublecrossed by Siebert, who is in league with Hedi's roommate, Zizi, to steal the jewels. Siebert is murdered by Zizi and her accomplices, and Larry and Hedi are charged with the crime. Zizi attempts to make a getaway aboard the Munich Express, but Larry leaps aboard the moving train to recover the jewels. The train stops on a drawbridge, and as Larry is on the point of retrieving the strongbox, the jewels slip into the river below. Zizi and her associates are brought to justice, and Larry and Hedi find consolation in their love.
