Night Tail is an adaptation of the original visual novel by Circle Kurosake Souko. The protagonist of the hentai is a girl warrior Knight who serves the forces of good and fights with the demons of sleep, which often attack the locals. Demons come into the dreams of the townspeople and torment them with nightmares. The dream world is called Paradise. Knight and her partner Mashiro must fight, defeat the demons and return to the normal world as