London, 1943. The Allied invasion of Sicily is weeks away — and Hitler knows it. To save thousands of lives, two British intelligence officers devise one of the most audacious deceptions in the history of warfare.
Ewen Montagu (Colin Firth) of Naval Intelligence and Flight Lieutenant Charles Cholmondeley (Matthew Macfadyen) of MI5 procure the body of a recently deceased Welsh vagrant, dress him as a Royal Marines officer with the rank of Major William Martin, equip him with carefully fabricated letters indicating the Allied invasion will target Greece and Sardinia rather than Sicily, and arrange for the body to wash ashore near the Spanish port of Huelva, where German intelligence agents are known to be active.
The deception worked. Hitler redirected armoured divisions to Greece. The Allied landings in Sicily in July 1943 succeeded beyond expectation.
Based on Ben Macintyre’s 2010 bestselling account, the film adds a romantic subplot in which both Montagu and Cholmondeley develop feelings for a female intelligence officer (Kelly Macdonald), bringing personal stakes to the story’s institutional courage. Johnny Flynn plays a young Ian Fleming — later the creator of James Bond — who worked in Naval Intelligence during the war.