A Czech takes the identity of a dead Englishman in a German POW camp and writes to the man's wife so that he won't be caught.
In June 1940 British prisoners march 200 miles from France to the Rhine. Ted (Jack Warner) recalls his family. Stephen (Derek Bond) remembers kissing Caroline (Jane Barrett). David (Gordon Jackson) is leaving on a train when he asks Elspeth (Margot Fitzsimons) to marry him.
As the prisoners board a train, Geoffrey Mitchell (Michael Redgrave) translates German. He remembers how he took the identity of a dead British soldier during a battle. The men march into the prison camp as Major Dalrymple (Basil Radford) maintains discipline. Celia Mitchell (Rachel Kempson) learns that her estranged husband is a prisoner and tells her father that she will write to him. In the barracks Mathews (Jimmy Hanley) stole a cigarette and is hit, and he apologizes. Geoffrey is suspected of being a German spy. He says he is Czech and escaped from a concentration camp, but he took Mitchell's identity. At first they get no letters and hear propaganda broadcasts. The men sing "Roll Out the Barrel."
Robert says goodbye to Caroline. David is blind and is told they can't operate. Red Cross parcels arrive, and they celebrate. Geoffrey reads David's letter from Elspeth and writes his answer, breaking the engagement. After guards search and find a tunnel, they confiscate amenities. The Kommandant asks Geoffrey why he has not written a letter. Geoffrey got a letter from Mitchell's wife, and he writes to her. Celia tells her father that Geoffrey has changed, and she reads the letter. Caroline tells Robert that Stephen got a letter that she is having an affair with him. Celia sends Geoffrey photos. Geoffrey writes of their little world in the prison camp.
New prisoners bring news. Geoffrey writes in November 1942 that they have no past or future. In March 1944 they talk about time. Stephen says he longs for Caroline. Dalrymple says that repatriation will be in one week for some, but Geoffrey is deferred six months. Dalrymple and a burglar plan to steal and alter the list so that Geoffrey can leave. During an air raid they cut barb wire and sneak into the building, find the list, and type in the name. One man is attacked by a dog and shot, but Geoffrey rescues him. Dalrymple jokes with the Kommandant as Geoffrey is being checked out.
The ship arrives, and Celia goes on board. Geoffrey sees her but says nothing. David gets home, and Elspeth says she knew about his eyes. Stephen finds Caroline leaving and says he loves her. Ted comes home. Geoffrey reports to headquarters as Karel Hasek and calls on Celia to tell her about her husband and how he came to write to her. She asks him to go. He says he fell in love with her and leaves. In May 1945 people celebrate, and he calls her.
This drama realistically portrays life in a prisoner-of-war
camp and shows how valuable were the Red Cross parcels. The importance
of letters is emphasized in how the Czech officer finds a completely
new relationship that inspires him.