After the Saints' victory against Hades, Seiya is left wounded and motionless in a wheel chair with no possible chance of recovery. Athena's sister Artemis, the Virgin Goddess of the Moon and twin sister of Apollo, makes an elaborate proposal - to restore Seiya's physical health in exchange for the supremacy of Sanctuary. Athena accepts and Artemis and her "Knights of the Sky" swiftly take control of Sanctuary. Now Seiya and his fellow Bronze Saints combat the forces of Zeus to regain their homeland but it will not be so easy. Bronze Saints Hydra Ichi and Unicorn Jabu, and Silver Saint Ophiuchus Shaina have join forces with Artemis and Apollo.
Summary taken from: MyAnimeList