Before the dawn of man or beast, immortals waged war against each other in Heaven. The victors declared themselves gods while the vanquished were renamed the Titans and imprisoned beneath Mount Tartarus. The Epirus Bow, a weapon of immense power, was lost on Earth during the war. In 1228 B.C., the mortal king Hyperion (Mickey Rourke) of Heraklion searches for the bow, intending to use it to release the Titans to spite the gods for failing to save his family. Hyperion captures the virgin oracle Phaedra (Freida Pinto), believing that she can find the Bow's resting place.
In a small village nearby, the inhabitants prepare to flee to Mount Tartarus to avoid Hyperion's army. One inhabitant, Theseus (Henry Cavill), is a skilled warrior trained by his mentor, the old man (John Hurt). Theseus and his mother Aethra (Anne Day-Jones), considered undesirables because Theseus was born from Aethra being raped, are forced to stay behind by Athenian soldiers including Lysander (Joseph Morgan). Theseus ably battles multiple opponents until the Athenian officer Helios (Peter Stebbings) intervenes and discharges Lysander for his actions. Lysander travels to Hyperion, offering his service and the village's location. Hyperion accepts, but maims Lysander for being a traitor. Hyperion's forces attack Theseus' village, murdering the villagers and Aethra, and taking Theseus captive.
The old man, revealed to be Zeus (Luke Evans), meets with his fellow gods Athena (Isabel Lucas), Poseidon (Kellan Lutz), Ares (Daniel Sharman),Apollo (Corey Sevier), and Heracles (Steve Byers), and warns them not to interfere in mortal affairs as gods, believing that, until the Titans are released, they must have faith in mankind to defeat Hyperion. Theseus is enslaved alongside the thief Stavros (Stephen Dorff). Phaedra, who is held captive nearby, sees a vision of Theseus. Phaedra organizes a riot, using the chaos to escape with Theseus, Stavros, and the other slaves. Theseus decides to pursue