One day, Kyutaro Horikita, the tall, dark and handsome cleaning expert of Kurokado High, comes across a sleeping maiden named Fumi Nishioka at school... Unfortunately, their meeting is anything but a fairy-tale encounter! It turns out Kyutaro is a "Sweeper" who cleans away negative energy from people's hearts--and Fumi is about to become his apprentice!

Fumi still has no memory of her past, but she begins to feel a sense of calm working and living with Kyutaro and his family of Sweepers. But when a Bug Handler goes after her, how will she overcome his dark manipulation?