The Captive Heart

The Captive Heart is a 1946 British war drama, directed by Basil Dearden and starring Michael Redgrave. The film was entered into the 1946 Cannes Film Festival.

He is suspected of being a spy by his fellow soldiers because of a few small errors and his fluency in the German language. Captain Grayson Guy Middleton wants to lynch him forthwith, but Major Dalrymple Basil Radford, the senior British officer, hears Hasek out and believes his story.To avoid suspicion, he has to maintain the fiction that Mitchell is still alive by corresponding with Mitchells widow Celia Rachel Kempson. Prior to the war, Mitchell had abandoned his wife and their two children, but the letters rekindle Celias love. ........

Source: Wikipedia