Iruma Ikaruga is living his best high-school life... until mascot-looking aliens from another world invade with their flesh-eating bugs, seemingly hell-bent on destroying humanity violently and effectively! On that fateful day, Iruma loses everything...his normal life, his best friend, and his crush...until six months later, when he catches a glimpse of her again. Is all hope for humanity-or just Iruma himself-truly lost?