The film stars several big names including Richard Burton, Robert Mitchum and Rod Steiger.

Burton (Sergeant Steiner) and Helmut Griem (Major Stransky) assume the roles played by James Coburn and Maximilian Schell respectively in the original film.

Starting in late May 1944, during the German retreat on the Eastern Front, Captain Stransky (Helmut Griem) orders Sergeant Steiner (Richard Burton) to blow up a railway tunnel to prevent Russian forces from using it.

General Hoffman (Curd Jürgens) orders Steiner to cross into nearby enemy territory and confer with American Colonel Rogers (Robert Mitchum) and General Webster (Rod Steiger), informing him that the High Command of the German Army (Wehrmacht) is plotting to assassinate Hitler and would like to surrender.

Breakthrough was mostly financed by West German producers when it was released in 1979, after several changes were made to the sequel: for instance, the action was relocated from Russia to the Western Front and Richard Burton replaced Coburn as Sgt Steiner.

The film was panned by critics, who identified a confusing plot, poor dialogue, an aged cast and undistinguished acting.