Colditz

Three British servicemen, Jack, Willis and McGrade, escape from a German POW camp, McGrade makes it over the border to Switzerland but the other two are captured and sent to Colditz - the most secure camp in eastern Germany. Back in London, McGrade seeks out Jack's fiancee Lizzie who is holding out for her lover's return. But he is drawn to her and is soon hatching a plan to persuade her that Jack is dead.