Due to his father's job, 15-year-old Hiroshi Kuzumi and his family move to the mountain town of Jouga. While some teenagers might have to worry about fitting in or feel out of place in a new environment, Hiroshi is welcomed enthusiastically at school by most of his new classmates. In fact, it seems like they just can't get enough of him, and he makes two friends rather quickly: the clingy and overly-affectionate Isuzu Tsumuhana, who is also his neighbor; and Kaname Asagiri, who also recently moved to Jouga. All in all, Hiroshi's new life seems to be quite normal—until people start disappearing.

Hiroshi is told that the missing townsfolk have simply moved away or suddenly transferred, but he can't shake the feeling that something is wrong. Meanwhile, in the dead of night under a red moon, masked individuals led by a girl with a scythe stalk their prey in the darkened streets of Jouga. Who are they, and are any of the residents safe from their wrath?