"The Demon Prince of Momochi House" is a supernatural fantasy anime based on the manga by Aya Shouoto. The story centers around Himari Momochi, a 16-year-old orphan who inherits the mysterious Momochi House on her birthday. The house, located on the border between the human and spiritual worlds, is inhabited by three supernatural beings: Aoi Nanamori, a humanoid spirit who serves as the guardian of the house; Ise, a shape-shifting Nue; and Yukari, a mischievous fox spirit. Upon her arrival, Himari discovers that Aoi has been bound to the house for centuries, tasked with protecting the boundary between worlds. However, Aoi’s existence is tied to a curse that transforms him into a demon at night, a state he struggles to control.

As Himari settles into her new home, she becomes entangled in the supernatural affairs of the Momochi House. She learns that the house attracts various spirits and yokai, some benevolent and others malevolent, and that her presence as the rightful heir disrupts the delicate balance between the human and spiritual realms. Aoi, initially aloof and resistant to her involvement, gradually forms a bond with Himari as she proves her determination to help him and the other inhabitants. Together, they navigate the challenges posed by malevolent spirits, ancient curses, and the lingering mysteries of the Momochi House’s past.

The narrative explores themes of identity, loyalty, and the coexistence of humans and spirits. Himari’s role as the bridge between worlds becomes increasingly significant as she uncovers the truth about her family’s connection to the house and the origins of Aoi’s curse. The dynamic between the characters evolves as they confront external threats and internal conflicts, with Himari’s compassion and resolve serving as a catalyst for change. The series balances episodic encounters with spirits and overarching plotlines, gradually revealing the deeper lore of the Momochi House and its inhabitants. Through its blend of supernatural intrigue and character-driven storytelling, "The Demon Prince of Momochi House" presents a tale of resilience and the enduring bonds that transcend the boundaries of worlds.