In this ferocious retelling of the Battle of Thermopylae, King Xerxes of Persia amasses an army of hundreds of thousands to invade and conquer the tiny, divided nation of Greece in 481 B.C. But when the advancing Persian forces enter the treacherous mountain pass of Thermopylae, they encounter Spartan King Leonidas and his royal guard of soldiers numbering just 300. According to legend, their valor and sacrifice inspired all of Greece to unite against the Persian foe.