During the Edo Period, 3 mysterious space capsules were sent down to earth. Fear that it might bring chaos to the earth, the humans at that time buried these 3 objects down beneath the ground and entrusted a piece of descriptive map to the Kamui family. Today, these 3 objects were awaken one by one. The first to awaken, Tri-Zenon, one of the Zenon Guardians is now driven by the descendant of the Kamui family, Akira Kamui
, his brother Ai Kamui
and his friend Kanna. Aliens who descend to earth with a purpose will now have to face Tri-Zenon.
, Ai Kamui
and their father have a serious problem: debt! Akira and Ai steal a family heirloom treasure map to keep the spoils for themselves, but an unfortunate distraction occurs: their city, Chitose, becomes the battleground for the military and an invading race of aliens! Falling into the lair of the treasure itself, the giant mecha Tri-Zenon, Akira, Ai and their friend Kanna now find themselves in the adventure of a lifetime: protecting Earth from the powers of Zenon Palace!