After Godzilla's meltdown destroyed Birth Island, the radiation transformed Little Godzilla into a sub-adult now called "Godzilla Junior." With nowhere to live, Junior began swimming back to his nest on Adonoa Island. Godzilla, now in critical mass, began to follow Junior back to the Bering Sea as well. Hoping to prevent Godzilla's meltdown from destroying the world, G-Force had Miki Saegusa use her telepathic abilities to lure Junior to Tokyo, hoping Godzilla would follow him there and fight and be killed by Destoroyah.