How 10,000 Spartans Brutally Avenged the 300 (The Battle of Plataea) This city lies in ancient Greece. In 480 BC, a massive Persian army invades. The Persian king, Xerxes, seeks to conquer all of Greece. But 300 Spartans stand in his way. They fall at Thermopylae, but their sacrifice is not in vain. The Spartans regroup, and 10,000 strong, they march towards Plataea. To avenge their fallen comrades, they prepare for battle. The stage is set for one of history's greatest battles. The two armies c