Adapted from the book by Frank Miller, this is a modern retelling of the Battle Of Thermopylae of 480 BC, when the 100,000 strong invading Persian Army of King Xerxes was held back in a narrow mountain pass by 300 Spartans. King Leonidas (Gerard Butler) is given four days by Persia's King Xerxes (Rodrigo Santoro) to lay down his arms and surrender. Rejecting the proposal, the battle ensues, and the Spartans are only defeated by the treachery of a local shepherd Ephialtes (Andrew Tiernan), who shows the Persians a secret route, enabling them to outflank their opponents.