At Binan High School in the city of Binan, Japan, Yufuin En and Kinugawa Atsushi, along with along with Naruko Io and Zaou Ryuu, enjoy leisurely high school lives while hosting meetings of a do-nothing club called the Earth Defense Club.

Elegant music plays in the background as the Binan High student council convenes. The council members: president Kusatsu Kinshiro, Arima Ibushi, and Gero Akoya wish to purge the world of fools by way of the Total Conquest of Earth's Lifeforms Project.

Long ago, two boys made wishes on a shooting star. One night in the student council room, Kusatsu thinks back on that day, and renews his oath of world domination. Meanwhile, the Earth Defense Club is holding one of its usual conversations about nothing in Kurotama Bath.

The rainy season's here, and the Defense Club is dedicating themselves to various indoor activities. Suddenly, they realize that Mr. Tawarayama -- whom Wombat is controlling under the pretext of preserving his life -- is covered in mold! The club erupts into chaos. Just then, Kinozaki and Tazawa of the Press Society burst in looking for material for a story. Kinozaki chases them around, trying to learn their secret, which stresses out Wombat, Yufuin, Naruko, and Zaou.

The Caerula Adamas plot a way to destroy the mysterious Battle Lovers. They also want to destroy the Defense Club, so as to cut down on club expenses. Thus, they declare that if the club members' scores on their final exams do not meet the average, the club will be dissolved. The Defense Club reluctantly gets to studying. Meanwhile, the student council also tries to scout the financially savvy Naruko to be their treasurer. When Gero offers him a salary during negotiations, Naruko casually agrees to leave the Defense Club. Soon, a monster appears, and the four remaining Battle Lovers must struggle to defeat it themselves.

Yufuin's inspiration leads the Defense Club decides to go on a training camp to the ocean on . Meanwhile, the three student council members head to a beach resort in a limousine. The beach has bright sun and white sand, but there's something a little off about it. A strange feeling starts hovering around the group's members...

As usual, Kinugawa and Yufuin are walking to Binan High School together as friends. But after a stop at the convenience store, Yufuin suddenly gets angry at Kinugawa and yells at him. A rift forms between the two, and soon a panic develops over them potentially leaving the Defense Club. Yumoto works blindly to try to get the two to make up, but Naruko and Zaou rebuke him for it. Will Yufuin and Kinugawa ever make up?!

Our Total Conquest of Earth's Lifeforms Project has reached a serious problem.

The normally cheerful Yumoto is acting strangely. His classmate, the manager of the baseball club, takes his temperature and reveals that he has a slight fever. The members of the Defense Club take him home to the Kurotama Bath, getting an eyeful of extreme brotherly love as Gora devotedly looks after his sick brother.

Binan High is preparing for their Culture Festival. Since the class that wins the popularity vote gets a cash prize, the Defense Club will participate as well. They'll be serving Kinugawa's curry and transforming into their Battle Lovers costumes to serve "Cosplay Hero Curry."

The clash between Kinugawa and Kusatsu has brought the true identities of the Battle Lovers and Caerula Adamas to light. Shocked, Vesta and Sulfur fight Perlite, and Cerulean faces Argent.