The Captive Heart is set in a German POW camp for British soldiers. Michael Redgrave plays a Czech patriot, who has assumed the identity of a deceased British officer to avoid being executed by the Nazis. When captured and placed in the camp, the British prisoners suspect the still-incognito Redgrave of being a spy. Only his conspicuous courage during an escape sequence vindicates the secretive Redgrave. The film's tinderbox tension is relieved with a joyous finale, which utilizes a fireworks display as adroitly as Hitchcock did in To Catch a Thief.