On her sixteenth birthday, orphan Himari Momochi inherits her ancestral estate that she's never seen. Momochi House exists on the barrier between the human and spiritual realms, and Himari is meant to act as guardian between the two worlds. But on the day she moves in, she finds three handsome squatters already living in the house, and one seems to have already taken over her role!

Himari Momochi inherits Momochi House, an estate which exists on the barrier between the human and spiritual realms. Himari is attacked by an ayakashi in the depths of Momochi House and is saved by the Guardian of the Gate. The guardian, wanting the Momochi name, tries to get Himari to marry him. Naturally, Aoi has no intention of letting him have his way!