A powerful local earthquake of magnitude seven strikes in Australia, thanks to explosives the Destrons have set off in their construction of an undersea base. Under orders from Ginrai, Lightfoot descends to the sea floor in robot mode to investigate. As he checks over an undersea volcano, he comes under attack by hundreds of Seacons, leaving him pinned under a large slab of rock. Ginrai and the Headmaster Jrs then travel there to rescue him. Super Ginrai goes by himself to rescue Lightfoot, where he is ambushed by King Poseidon, who causes an avalanche on top of them. Meanwhile, the Headmaster Jrs. are working to evacuate the people from the ruined cities.