While aboard a cruise ship for the evening, Yuriko finds a child's doll, which suddenly speaks to her. The voice introduces itself as Zemi, an alien from the Planet Ruparts, and warns of an invasion from outer space. Shocked, Yuriko throws the doll overboard, but Jun and Ippei take little heed to her story.

Joe Aikawa, better known as Dynamite Joe, takes Japan by storm as he rises through a series of decisive victories to become the country's new boxing champion. Prior to the match for the world championship title however, Joe mysteriously disappears from the sports world, creating controversy towards his promoter.