Set halfway through Kratos' ten years servitude to the Gods, Chains of Olympus begins with Kratos being dispatched to the city of Attica to help defend it from the invading Persian army. Soon after his arrival, the Spartan spots a basilisk climbing over the city walls and gives chase. During his chase, Kratos confronts the Persian King inside the city and kills him. Taking the King's power to summon the Efreet, he then encounters the basilisk and kills it. After defeating the basilisk, he witnesses the sun fall from the sky, plunging the world in darkness. Following the dim remaining light on the horizon, Kratos fights his way through the city of Marathon, along the way encountering the black fog of Morpheus, which now covers the land in darkness.Eventually, Kratos makes his way to the Temple of Helios, the source of the remaining light, and the Sun Chariot. He encounters a statue of Athena, who tells him that Helios has disappeared and Morpheus has used this to his advantage to cause the gods to fall into a deep slumber. Athena wants Kratos to retrieve Helios so he can release Morpheus' grasp on the other gods and his power over the Earth. Along the way, Kratos is haunted by a strange melody, which he later recognizes as a song played by his daughter, Calliope. Making his way through the Temple of Helios, Kratos encounters Helios' sister, Eos, who promptly sends him to the caves within the Temple of Olympus. She guarantees Kratos the gods will relieve him of his nightmares if he agrees to save Helios from the Titan Atlas, who abducted him. Casting her promise aside, as the gods betrayed him before, Kratos nevertheless agrees, albeit reluctantly, to save Helios. Kratos then retrieves the Primordial Fire needed to awaken the Fire Steeds from the cave and returns to the temple.After restoring the fire steeds back to life, the horses lead Kratos into the Underworld before retreating. There, Kratos witnesses the breaking of the chains binding Atlas to the pits of Tartarus. After some time, the Spartan fights and climbs his way out of Tartarus, returning to defeat Charon. Seizing control of the ferry, he follows the light of Helios, currently illuminating the underworld, down the river Styx, coming upon the Temple of Persephone. To his own surprise, he sees his daughter Calliope on the shorelines of the temple and follows her inside. Unable to locate her, instead he meets Persephone, Queen of the Underworld.Persephone tells Kratos that Calliope is in the Elysium Fields and that the only way to see her again is for Kratos to "release" all of his past evils and become worthy of Elysium, giving up his powers given to him by the gods; however, Persephone warns him that the world will suffer for his choice. After transferring his power into the Forsaken Tree, which included all of his weapons, his magic, and relics, Kratos regains his humanity, becoming a normal man and being reunited with his daughter. However, Persephone appears: she taunts and mocks Kratos' choice and reveals to him her true plans. Kratos realizes now that if he stays with his daughter, it would mean the end of the world for everyone, including Calliope and himself. ThBecause of this, he once more becomes the Ghost of Sparta, regaining his characteristic appearance. After which, Calliope breaks down crying at the sight of a reborn Kratos, who presses on.With his skills restored, Kratos pursues Persephone, catching her at the base of the pillar. She tells him it is the end, then reveals her other form - a winged woman wearing black armor - before carrying Kratos to the top of the pillar. Once they reach the summit, Kratos and Persephone engage in a bloody final battle; during the battle, Persephone tries to subdue and confuse Kratos, urging him to go back to Elysium and be with Calliope, and when he resists, she orders Atlas to destroy him. Kratos chains Atlas to the roof of the underworld before returning to battle Persephone and eventually killing her with the Gauntlet of Zeus. Dying, but uncaring of her fate, the goddess taunts Kratos, snarling that now his suffering shall never end as her body then explodes, severing the pillar in the shockwave with Atlas now the only thing holding the world together. Though the Titan to gloats to him about the gods' true plans for him, Kratos believes his path is clear, serving them regardless so they will keep their promises to free him from his nightmares as it is all he has left. Atlas ends by foretelling that they will meet again.Keeping his own promise to the gods, Kratos returns Helios to the sky. But he is left with the knowledge that his sins have consumed him, forsaking his daughter as his destiny was not to be with her. Weak from battle, Kratos falls unconscious from the sun chariot but is suddenly stopped before striking the ground, being placed on the cliffs that he would later jump from in the original God of War.