In the 25th century, a ship carrying 300 people leaves Earth to find a new home, but an accident sends it into a black hole linked to another universe. The passengers drift in an emergency capsule to Ismo, the sole surviving planet of the Onam System, and the story picks up twelve years later. Long ago the gods sealed the eight-headed monster Yamatano Orochi inside eight stones, one at the heart of each planet. Tsukuyomi, the evil god ruling the comet Yomi, destroyed seven planets with his robots, the Sky Warriors, but lost the strongest, Susanoo, while reaching for the last stone. A million years on, Yomi returns, and Tsukuyomi sends eight Sky Soldiers to recover Susanoo. The robot now answers to Takeru, a 13-year-old boy from Earth who unearthed it and woke it, drawing him into the fight to defend his friends and their planet.