Hisaki and Yasha are an odd pair of friends: Hisaki is quiet, distant, and possibly keeping secrets from everyone, while Yasha is loud, violent, and in serious need of anger management. As they try to deal with each other, they soon find that creatures are after them for something they know nothing about: a demon supposedly hiding within one of them.
The group dispenses with the ninja guards, but it's too late - the alarm has been sound. Their battle is not over, as another enemy waits nearby, ready to strike.