The Red Danube (1949)

Shortly after the end of World War II, British Colonel Michael S. "Hooky" Nicobar (Walter Pidgeon) is assigned to a unit in the British Zone of Vienna. His duty is to aid the Soviet authorities to repatriate citizens of the Soviet Union, many of whom prefer not to return to their home country. Billeted in the convent run by Mother Auxilia (Ethel Barrymore), Nicobar, and his military aides Major John "Twingo" McPhimister (Peter Lawford) and Audrey Quail (Dame Angela Lansbury), become involved in the plight of young ballerina Olga Alexandrova (Janet Leigh), who is trying to avoid being returned to Moscow. Nicobar's sense of duty is tested as he sees first hand the plight of the people he is helping return to the Soviet Union; his lack of religious faith is also shaken by his contact with the Mother Superior.