In ancient times, the gods Zeus, Poseidon, and Hades betrayed their parents, the Titans, and banished them to the Underworld with the help of the Kraken, a sea monster born of Hades. The gods divided the Universe among themselves; Zeus took the skies, Poseidon took the seas, and Hades, tricked by Zeus, was left with the Underworld. The gods created the mortals, whose faith in them assured their immortality; however, as time passed, mortals began to question them. Years later, "Perseus" is fishing with his family when they witness soldiers from the city of Argos destroying a statue of Zeus. The gods, infuriated at this desecration, unleash the Furies - flying beasts who pursue mortal sinners. The furies attack the soldiers and destroy the fishing vessel. Only Perseus survives and is found by a group of soldiers from Argos. Perseus is brought before King Cepheus and Queen Cassiopeia who are celebrating the campaign against the gods. Queen Cassiopeia brashly compares her daughter Princess Andromeda to the gods and boasts she is more beautiful than Aphrodite. The revelry is cut short by the arrival of Hades, who has been given leave by Zeus to punish the mortals for their defiance. Hades states that he will unleash the Kraken against Argos unless Andromeda is offered as a sacrifice. Before leaving, he reveals that Perseus is a demigod, the son of Zeus. In captivity, Perseus meets Io, who tells him of his origin. Io also reveals that she was cursed with immortality after she refused Poseidon's advances and has watched over Perseus his entire life. She has always protected him, as he is the only one who can defeat the gods. Perseus is asked to lead the King's Guard to visit the Stygian Witches in order to discover a way to kill the Kraken. Wishing to avenge the death of his family, Perseus accepts. Zeus is convinced by Apollo to give Perseus a chance and presents him with an enchanted sword forged on Mt. Olympus and a winged horse named Pegasus. Perseus refuses both gifts but Draco puts the sword into safekeeping. Shortly thereafter, they are attacked by Calibos. Draco severs Calibos's hand causing Calibos to flee. The band gives chase but is attacked by giant scorpions called Scorpiochs summoned by Calibos’s blood. They are saved by the Djinn, a band of non-human desert sorcerers led by Sheik Suleiman. The Djinn, also wishing for the gods' defeat, lend their aid to Perseus and his band. The group arrives at the lair of the Stygian Witches and learns from them that the only possibility for killing the Kraken lies with the head of the gorgon Medusa who resides in a temple in the Underworld. Medusa can turn any creature made of flesh into stone that makes eye contact with her gaze, and thus using her head is the only way to stop the Kraken. Perseus, Io, Suleiman, Draco and his remaining men Solon, Eusebius, and Ixas cross into the Underworld and enter Medusa's temple lair while Io remains outside, unable to enter the temple as a woman. Suleiman and Draco both wound Medusa, sacrificing themselves in the process and setting the stage for Perseus to behead her with his eyes closed. As he is leaving the temple with Medusa's head, he witnesses Calibos appear behind Io and fatally stab her. Perseus and Calibos engage in mortal combat and as he finally comes to terms with who he is, Perseus picks up the Olympian sword and pierces Calibos through the chest. Before dying, Io urges a reluctant Perseus to leave her and save Andromeda and Argos before she dissolves into a golden ethereal vapor. Perseus mounts Pegasus and hastens back to Argos as the solar eclipse begins and Zeus orders the Kraken's release. The Cult goes to the palace and seizes Andromeda in order to offer her to the Kraken. In an intense aerial chase with Perseus riding Pegasus, he manages to retrieve the bag and expose Medusa's face to the Kraken, making eye contact just before it is able to eat Andromeda. The Kraken slowly turns into a massive stone statue which cracks and falls apart. Perseus raises his sword to the heavens and calling upon Zeus, throws his sword at Hades. A lightning bolt engulfs the sword which expels Hades and banishes him to the Underworld once more. Perseus rescues Andromeda, now the rightful Queen of Argos. Andromeda asks Perseus to stay by her side as King, but he declines. Perseus also refuses another offer of godhood from Zeus, who then states that if Perseus is to live as a human he should not be alone, and subsequently revives Io.