Sekai ka Kanojo ka Erabenai

Even though Kouki 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, Jindou-san, announces that she's Kouki's girlfriend! She tells Kouki that he can never tell Ayumi his true feelings...because if he does, the world will end in apocalypic disaster? What's a guy to do?
(Source: Kodansha USA)
Note: Includes 5 extra chapters.