Shintarou Kisaragi's existence as a shut-in would have been ideal were it not for Ene, a cyber girl residing in his computer. Lively and cheerful, she delights in playing pranks, standing in stark contrast to his own apathy. It is Ene's daily mischief that causes his keyboard to break. The prospect of being unable to use his computer becomes unbearable, prompting him to go out and replace it. Thus, in the peak of summer heat, Shintarou steps out of his room for the first time in two years. However, this routine shopping errand takes a dark turn when a group of terrorists threatens the department store, and he is taken hostage alongside other shoppers. Caught in this crisis, he encounters the "Mekakushi-dan," a mysterious group of teenagers possessing red eyes and strange abilities. Although their meeting appears to be a matter of chance, Shintarou must rely on their assistance to save the department store. Yet, the destinies of these teenagers are more deeply connected than they appear, leaving them to question whether their encounter was anything but coincidence.