We are entering spring vacation where Nagi spends her days playing video games, reading manga, and watching anime until she falls asleep. Video games, manga, anime and sleep. Her routine was broken when Hayate needed to get a new cell phone. They went to a shop in Shinjuku and for the mere moment that Hayate purchases a cell phone, Nagi wanders around and gets lost. She ends up in the "Lost Children" center where a duel between two lost children is about to begin.