Richard Thomas, Horst Buchholz, José Ferrer, Ute Christensen, Jacques Breuer, Nicholas Farrell, Kenneth Griffith, Robert Freitag, Gerald W. Abrams, Ilse Bahrs, Pasqual Breuer, Carl Duering, Josef Ernst, Klaus Götte, Günther Maria Halmer
In Berlin in 1961, an American soldier and a German engineer join forces to build a tunnel under the Berlin Wall in order to smuggle out refugees, including the soldier's East German girlfriend.