In the story, the high school "Earth Defense Club" is basically the "do nothing club." Club members En and Atsushi are soaking in the bathtub at a public bath when suddenly a mysterious pink creature, Wombat, appears out of thin air and asks, "I want to save this star... please would you lend me your power?" Then, Yumoto, whose family runs the bath house appears and chases wombat to give him a hug. In school the next day, the remaining two members, Io and Ryū, also meet Wombat. Wombat gives all five of them bracelets and tells them to protect Earth. A dazzling light comes from the bracelets and envelops their bodies...