Adopted from the epic graphic novel by Frank Miller, the film is set during the Persian-Greco war at the Battle of Thermopylae, where Spartan King Leonidas (Gerard Butler) and 300 Spartans fight to the death against Xerxes (Rodrigo Santoro) and his massive Persian army. Their bravery and sacrifice against their out-numbered odds then inspire all of Greece to unite against their Persian enemy, which lead to the origins of democracy.