In ancient Greece, the city of Athens faces an overwhelming invasion by the Persian Empire. When the powerful Spartans are unable to assist due to a religious festival, the Athenian generals Calamachus and Miltiades must defend their home alone on the plains of Marathon. After a brilliant surprise attack drives the Persians into a swamp, the Greeks realize the enemy fleet is sailing toward an undefended Athens to trick the city into surrendering. Philippides, a wiry and exhausted messenger who had already run hundreds of miles to Sparta and back, volunteers for one final, desperate mission. Shedding his armor to move faster, he takes a treacherous mountain shortcut, overcoming a broken shoulder and agonizing pain. He reaches the city gates just in time to announce "Victory!" before collapsing into a deep sleep. His heroic run saved Athens  ...