It's not unusual for lady-killer Renzaburo Taki to share a night with a woman. When that woman can turn into a demonic spider, however, it's just a little worrying. The demons are on the move, and as a member of the Black Guard, Taki's job, his real job is to protect the human world from the demon world. And his work is just beginning! A fragile peace exists between the two worlds, brokered by a treaty. In order for the renewal of that treaty to go smoothly, Taki has to protect Giuseppi Mayart, a two hundred year old man with immense spiritual power, from an extremist faction of demons seeking to bring chaos to the two worlds.