Even though Koki Nakagawa and his childhood friend Ayumi Fujisaki bicker like cats and dogs, one thing's for sure...he's head-over-heels in love with her. But when he finally starts to confess his feelings, his awkward-but-nice-enough classmate, Jindo-san, announces that she's Koki's girlfriend! She tells Koki that he can never tell Ayumi his true feelings...because if he does, the world will end in apocalyptic disaster? What's a guy to do?