Yayoi Hamazaki, a special agent of the International Defense Force, embarks on a mission to investigate a city where humans have suddenly vanished. During her investigation, eerie soldiers appear. Sensing danger, Yayoi transforms into Blue Kagelenger and defeats the combatants one after another. When she tracks down their hideout, she's confronted by the super-strong monster Agon. After a fierce battle, she manages to defeat him, but his final word—"energy"—deeply unsettles her. Following Agon's defeat, the female boss Sorou appears. Placing her hand on Agon's body, she performs a mysterious act: Agon miraculously rises again. Sorou's ability is the power to freely manipulate energy. With this power, Agon returns to the battlefield. Blue stands against Sorou's overwhelming strength, and their clash transcends mere combat, heralding a new crisis. The story then plunges into even deeper and more dramatic developments.