Shintarou Kisaragi's life as a shut-in would have been perfect if not for the cyber girl Ene, who lives in his computer. Upbeat and cheerful, she enjoys playing pranks, in complete contrast to his own apathy. It is due to Ene's daily antics that his keyboard breaks. The dread of not having the use of his computer is too much to bear, and he sets out to replace his keyboard.

And so, in the dead heat of summer, Shintarou leaves his room for the first time in two years. However, this simple shopping trip takes a turn for the worse when the department store is threatened by a group of terrorists, and he is taken hostage along with the other shoppers. Tied up in this crisis, he meets the "Mekakushi-dan," an enigmatic group of teenagers with red eyes and strange powers. Seemingly brought together by chance, Shintarou must save the department store with their help. But the fates of these teenagers are more intertwined than they seem, and they are left to wonder whether their meeting was more than mere coincidence.