Himari Momochi inherits Momochi House, an estate that exists on the barrier between the human and spiritual realms. Aoi is the human Omamori-sama, or guardian of the house, who can transform into a powerful spiritual being. But once Momochi House had chosen Aoi as its protector, all evidence of his existence in the human world was erased, and he has never been able to leave. Can Himari break Aoi free?