In the near future, humans will communicate almost exclusively through online networks – face-to-face meetings are rare and the surveillance state nearly all-powerful. Even school children are only allowed to meet in the flesh on school grounds. So when a serial killer starts slaughtering students, the crackdown is harsh. And despite all the safeguards, the killer's latest victim turns out to have been in contact with three young girls; Mio Tsuzuki, a certified prodigy; Hazuki Makino, a quiet but opinionated classmate; and Ayumi Kono, her best friend. As the girls get caught up in trying to find the killer – who might just be a werewolf – Hazuki learns that there is much more to their monitored communications than meets the eye.