The story takes place in East Berlin soon after the Berlin Wall is built, and is based on an actual escape on January 28, 1962. Kurt Schröder is a chauffeur to East German Major Eckhardt and his seductive wife Heidi, and lives within sight of the Wall. Kurt is having an affair with Heidi. One night he sees a friend, Günther Jurgens, who works at the garage where Kurt has the Major's car maintained, drive his truck into the wall, and get killed trying to escape to the west. Günther's sister, Erika, comes looking for Günther when he doesn't return, and is told that Kurt saw him last night. She then goes to Kurt's house, where he lives with his mother, Uncle Albrecht (a musician), sister Ingeborg and kid brother Helmut. Erika is intent on escaping to West Berlin, thinking that her brother made it. Kurt, reasonably satisfied with his life, has no intention of risking his life to attempt an escape. Erika then looks out beyond the barbed wire, but Kurt catches her as she tries to crawl under, and they pretend to be lovers to hide her intentions from suspicious guards. Kurt then hides her in his house. A piece of Erika's clothing is caught in the barbed wire, and the guards track her to the Schröder's house. She hides in a room without a floor, and narrowly escapes the guards after they conclude that she could not be in the room.
The Schröders and their neighbors, including a woman named Marga whose husband has already escaped to the west, want to escape East Germany. Kurt comes up with the idea of building a tunnel under the wall, through which they can escape to West Berlin. Although he will mastermind the plan, Kurt has no intention of going with them as he feels he can better serve them by staying behind and being their cover. They drill through the basement wall using Uncle Albrecht's band as a noise cover when the actual drilling takes place. One member of the family keeps watch while the others work on the tunnel itself. After they start digging the tunnel, they are joined by Walter Brunner, to whom Kurt's mother has promised to rent a room. All the while, Kurt is falling in love with Erika, and he eventually summons the courage to tell her that her brother is dead. Because of this burgeoning love, Kurt has changed his mind and will escape with the rest of his family and Erika. On January 27, 1962, the tunnel is completed when just before dawn Kurt reaches the other side, and the breakout is planned for the following night.
However, Marga tells Erika's parents the news of their daughter, and Erika's father, a professor who favors the Communist regime, betrays the escape plan to Major Eckhardt. Kurt learns from Heidi that the authorities are after him (she not knowing why), and he hurries home. When he arrives home, Kurt learns that his family have invited Uncle Albrecht's band members to join the escape, bringing the number of escapees to 28. Kurt tells them of the betrayal, and that they must make their escape immediately. As the police besiege their house, the Schröders, their friends and Erika make their escape, with Kurt bringing up the rear. He is wounded when a soldier fires, and struggles to make his way through the tunnel as he collapses it behind him, but Erika comes back to find and help him. Together they make their way to the exit, where the others have already emerged to live in freedom.
Don Murray as Kurt Schröder
Christine Kaufmann as Erika Jurgens
Werner Klemperer as Walter Brunner
Ingrid van Bergen as Ingeborg Schröder
Carl Schell as Major Eckhart
Edith Schultze-Westrum as Mother Schröder
Bruno Fritz as Uncle Albrecht
Maria Tober as Marga
Horst Janson as Günther Jurgens
Kai Fischer as Heidi Eckhart
Kurt Waitzmann as Prof. Thomas Jurgens
Helma Seitz as Frau Jurgens
Ronald Dehne as Helmut Schröder
Since the building of the Berlin Wall in 1961 stories of escapes from the East, both failed and successful, had filled the news in the West and led to competition between US networks to record a tunnel escape. MGM decided to take advantage of the public interest with a feature film inspired by real events. This included building a 300 yard long plaster replica of the wall in West Berlin that became a tourist attraction and attracted the attention of East German guards. The movie crew filmed sentries flashing spotlights across the border, turning them into film extras and prompting director Robert Siodmak to rave “Talk about realism!"
According to MGM records, the film made a profit of $193,000.