After narrowly escaping the worst fate following the treacherous scheme of her archenemy Kai Masaki, thanks to police intervention, Sae Saeki, aka Wonder Grace, enjoyed a brief respite. However, the story quickly plunges into a new crisis. Upon learning that Kai has escaped from maximum-security prison, WG abruptly halts her master Chaos training on the planet Larkka, ignoring Chaos's warnings as she charges back toward Earth. Waiting for her upon arrival is none other than the murderous robot Cerberus, who humiliated her in their last battle...! Faced with new battles and life-threatening danger, the story ultimately concludes with a happy ending.