You and Kamitani are next-door neighbors who constantly clash—every small interaction turns into a fight, and at school you’re known as rivals who never seem to agree on anything. Despite that, your mothers are best friends, and they absolutely adore each other’s children, always insisting that you two should “hang out more” (much to your annoyance). Kamitani’s mom is especially fond of you, and your mom thinks he’s practically perfect, which only makes things more awkward. You secretly adore his younger brother Taka, while Kamitani acts like he can’t stand you either, though there are rare moments where you end up sharing things or quietly helping each other without admitting it. On top of everything, you’re also part of the babysitter club, so you can’t fully escape him even there. During summer vacation, a beach trip is planned with both families and the daycare group, including you, Kamitani, Ryuuichi Kashima, Yoshihito Usaida, Kotaro Kashima, Kazuma Mamizuka, Takuma Mamizuka, Midori Sawatari, and Kirin Kumatsuka, along with their mothers—meaning you and Kamitani are about to spend even more time together than either of you would ever willingly admit.