It is spring 480 BC, Persian King Xerxes, continuing his father Darius' master plan to conquer the Hellenic city-states, arrives in Hellas. The previous Persian invasion and diplomatic attempts have already turned most northern Hellas tribes and states to the Persian side. But the people of Athens and Sparta, the largest Hellenic powers at the time, feel quite insulted by the Persian emissaries' request to surrender to Xerxes, and so slay them. In Sparta, King Leonidas consults the local oracle, who in her trance decrees that Sparta must not go to war, lest they interrupt a sacred festival and thus anger the gods. Despite his instructions, Leonidas gathers 300 of his best soldiers, under the guise of a leisurely walk. As they march north, the Spartans are joined by a group of Arcadians and various other Greeks, shortly before arriving at the Hot Gates of Thermopylae, where they meet Ephialtes, a hunchbacked Spartan who wants to join the 300 and warns Leonidas about a secret goat path the Persians could use to outflank and surround them. Using courage and the great battle skill of his men, Leonidas defends Thermopylae until the embittered Ephialtes betrays the Spartans by telling King Xerxes about the secret passage leading to the back of Leonidas's army. Meanwhile, his wife Queen Gorgo of Sparta tries to convince the council to send the Spartan army to assist Leonidas and the 300.

300 at IMDb