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 awake as a Queen? Fumi has never shown much romantic interest in Kyutaro, the quiet but formidable Sweeper who may be the only one who can keep Fumi's power under control. But when Kyutaro tells her that he'll never leave his side, she unexpectedly starts to fall for him!