Rin and Yukio were chasing down a demon, the usual sort of thing to do on a Saturday afternoon. Well, the demon manages to escape the two exorcists. Even worse, they're lost in the woods and are a good few hundred kilometres away from civilisation. Instead of finding the demon, the twin brothers stumble upon two strange women with stranger markings. As it turns out, the ladies are demon slayers and kill for fun. Before they can eliminate the boys, however, it seems that they need their help. Apparently, saving the world is more important than exterminating the sons of Satan.