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?

Fumi finds out that she has both a White Queen and a Black Queen inside of her, and she must train her mind and body in order to become the true Queen. Kyutaro vows to protect Fumi, but will he be able to do anything when other gatekeepers go after her power?