The "Day of Calamity" in 2045――. Suddenly, mysterious giant creatures appeared from the sky, invading major cities like Tokyo, NY, and LA. Mankind continued to be threatened by these creatures, which they called "Insects." Ten years have passed since then, and humanity has found a way to resist the daily invasions. It is the "human weapon," born by integrating bio-computer cells into the orphans of the "Day of Calamity." Jun Amamiya, an orphan of the "Day of Calamity" who was turned into a weapon, continues to exterminate the hateful "Insects" as the "Guardian Deity of Peace: Prometheus"! And as the inter-species struggle against the "Insects" intensifies, he touches the abyss of this great war――!!