Fumi Nishioka lives with Kyutaro Horikita and his family of Sweepers, people who specialize in cleaning the minds of those overcome by negative energy and harmful spirits. Fumi has always displayed mysterious abilities, but will those powers be used for evil when she begins to truly awaken as a Queen?

Even though Fumi has the ability to kill the snake that's sealed within Kyutaro, she can't do so without killing Kyutaro in the process! Kyutaro strikes a deal with the snake, but can he make good on his promise if it means facing a prospective leader of the Seiryu Clan who has a snake inside him as well?