Floating off the coast of Southern Spain, the discovery of a British Royal Marine was considered a major intelligence coup for the Germans. Documents inside the soldier's attache foretold an Allied invasion that prompted the Nazis to transfer their troops and fortify the coast. What the Germans didn't know was that the body belonged not to a British officer, but to a Welsh tramp who'd been planted within their reach as a mode of Allied counterintelligence. Operation Mincemeat would be the Trojan Horse of World War II, that may have saved thousands of lives and pushed the Allies towards victory.