The Devil Makes Three (film)

The Devil Makes Three is a 1952 thriller film set in postWorld War II Germany, starring Gene Kelly, Pier Angeli and Richard Egan.

He learns that most of the family was killed by an American air raid. The only survivor is the daughter, Wilhelmina Lehrt, who is working as a bar maid in a nightclub and hates Americans. Eliot nonetheless manages to romance Willie and in his time at the nightclub, he develops a friendship with Heisemann, a comic.Heisemann, it turns out, has secret ties to an underground Nazi revivalist movement. When Eliot discovers this, he tells his superiors, who order him to continue his relationship with Willie to learn more about Heisemanns operation. ........

Source: Wikipedia