During the Edo Period, three mysterious space capsules descended to Earth. Fearing they might bring chaos, the people of that era buried these three objects underground and entrusted a fragment of a descriptive map to the Kamui family. Today, these three objects have awakened one by one. The first to awaken is Tri-Zenon, one of the Zenon Guardians, who is now piloted by Akira Kamui, a descendant of the Kamui family, his brother Ai Kamui, and his friend Kanna. Aliens descending to Earth with a specific purpose will now have to face Tri-Zenon.