美男高校地球防卫部 HAPPY KISS！

In the city of Mayonai, located in northern Kanto, Japan— The "Earth Defense Club (lol)" at Mayonai High School remains a club that does nothing as usual... Its members, Shūzenji Kyōtarō, Kirishima Ryōma, Wakura Nanao, Manza Taishi, and Dōgo Ichiroku, idly enjoy tea time and chat about worthless, silly topics—that's the kind of club it is. After school, everyone heads to "Kurotama Hot Springs." Shūzenji sinks to the bottom of the bath from sheer comfort, and when Kirishima pulls his arm up, they fish up a strange, beautiful boy along with him. "I am Prince Karls, the first prince of the Honēra Kingdom's royal family! I have come to HAPPILY rule over all of you ☆" And just like that, the five are dragged into a succession dispute in a magical kingdom...