The film begins with the Persian Emperor Xerxes (Rodrigo Santoro) seeking to conquer Greece, and King Leonidas, who is determined to protect his kingdom. The Spartans, along with a few other Greek city-states, prepare to face the massive Persian army in the narrow pass of Thermopylae. Despite being vastly outnumbered, the Spartans, known for their superior combat skills and bravery, put up a fierce resistance against the Persians.