Jean-Pierre Aumont (billed simply as Pierre Aumont) makes his American film debut in Assignment in Brittany. Set during WW2, the film casts Aumont as Free French captain Metard, who bears a remarkable resemblance to Bertrand Conlay, a prisoner of the Allies whom is suspected of being a fifth columnist. Posing as Conlay, Metard gains the confidence of the Nazi occupiers of Brittany. He plays his part to the hilt, even unto romancing Conlay's patriotic girlfriend Anne Pinot (Susan Peters). This being a standard-issue "underground" melodrama, the film ends with a life-and-death contretemps with the Nazis, excitingly staged by director Jack Conway. Assignment in Brittany is based on the best-selling novel by Helen Macinnes.