A fresh twist emerges in the Dangaioh saga as a mysterious explosion rocks Futagami Island. Intent on wreaking havoc on the planet, the Tartarus Knights - led by the wicked Professor Katou - plan to accomplish their goal through a meager research facility on the island. Despite their dominance, a highly advanced fortress guarding the island poses a threat. But when three humanoid robots emerge from the fortress, it's revealed they're none other than the powerful Dangaioh, ready to fight back.