Perseus (Sam Worthington) has a big albatross around his neck: his father is Zeus (Liam Neeson), which makes him only half a god, and the object of much attention by the jealous coterie of gods around Zeus. When the Greek city of Argos shows contempt for Zeus, his brother Hades (Ralph Fiennes) wants to show some vengeance. The city decides to sacrifice Princess Andromeda (Alexa Davalos) to placate the gods, but Perseus decides to save her from the monsterous Kraken. His mission is complicated when gods take sides to help or hinder his progress. Io (Gemma Arterto) remains a steadfast spiritual guide. Poseidon (Danny Huston) and Apollo (Luke Evans) offer their assistance in the race to save Argos from divine wrath.