Watch on the Rhine (1943)

Sara and Kurt Muller and their three children are returning to her mother's home in Washington DC after 18 years in Europe. A Romanian Count living there discovers Kurt's attache case full of money. He also finds out from friends at the German Embassy that Kurt is working with an anti-Nazi underground group in Germany. He tries to blackmail Kurt. Kurt shoots him and must flee. When Sara hears no more of Kurt, she knows that her oldest son Joshua will soon leave to work in the underground.