Binan is a city somewhere in Japan. The "Earth Defense Club" at Binan High School was a club that did absolutely nothing. When club members Atsushi Kinugawa and En Yufuin were chilling out while soaking in the hot tub at the bathhouse Kurotamayu, a pink beast (Wombat) suddenly appeared out of thin air. "I want to save this planet... can you please lend me your strength?" The two feel the mood has been ruined by Wombat, who talks to them in Japanese about how he wants to save Earth with the power of love. Just then, the son of the bathouse owner Yumoto Hakone shows up, and as soon as he sees Wombat, he chases it, screaming "Let me fluff you up!"
The next day, Kinugawa and Yufuin are caught by Wombat once again at school along with the other club members Io Naruko and Ryu Zaou. Bracelets clasp onto the wrists of these four, along with Yumoto Hakone, who bumped into them after chasing after Wombat, with a command that they must save the Earth. "It's about love-making!" they hear as a bright light emanating from the bracelet envelops their entire bodies. The five transform into the "Battle Lovers," the heirs to the throne of love...