In 1943, British Intelligence needed Hitler to believe the next Allied landing would come in Greece and Sardinia, not Sicily. Their solution was a corpse. Dressed as a fictional "Major William Martin" and carrying forged secret documents, the body was released off the coast of Spain, timed and positioned so Spanish authorities would recover it and pass its contents to German intelligence. This episode of Secrets of World War II reconstructs the planning behind the ruse, the intelligence officers who invented Martin's entire paper identity down to love letters and theater tickets, and the real, unnamed man whose body was used. It follows the operation's aftermath, tracing how convincingly the deception landed with German command and what it meant for the thousands of Allied troops who went ashore in Sicily against weaker defenses than planned. Archival photographs, period documents, and expert interviews carry the account, alongside the later research that finally identified the man behind Major Martin. The result is a close look at how a single fabricated identity reshaped a real invasion.