 God of War : Chains of Olympus was first released in North America on March 4 , 2008 , for the PlayStation Portable . Its narrative takes place during Kratos ' ten years of service to the gods . Kratos halts a Persian invasion of the Greek city of Attica , and learns that the world has been plunged into darkness by the god Morpheus . Kratos investigates the abduction of the sun god Helios , and prevents the Machiavellian plan of the goddess Persephone to use the Titan Atlas to destroy the world . 
