"Wagaya no Oinari-sama" centers on the Takagami brothers, Noboru and Toru, whose lives take an unexpected turn when they encounter a powerful fox spirit named Kuu. After their mother falls mysteriously ill, the brothers learn that their family has a long-standing connection to the spiritual world. Kuu, a divine being who once served as their family’s guardian deity, is summoned to protect them from supernatural threats. Kuu’s arrival introduces the brothers to a hidden world of gods, spirits, and mythical creatures, blending everyday life with the fantastical.

Kuu, who can shapeshift between a male and female form, is a playful yet formidable presence, often using their powers to assist the brothers while navigating the complexities of human emotions. The narrative explores the growing bond between Kuu and the Takagami family as they face various challenges, including malevolent spirits, rival deities, and the consequences of meddling with the spiritual realm. Alongside Kuu, other characters such as Mizuchi, a water dragon, and Sakura, a shrine maiden, play significant roles in aiding or complicating the brothers’ journey.

The story balances episodic adventures with an overarching plot, delving into themes of family, loyalty, and the coexistence of humans and spirits. As the brothers uncover more about their family’s history and Kuu’s past, they must confront their own fears and responsibilities. The series combines humor, action, and heartfelt moments, creating a narrative that intertwines the mundane and the mystical while exploring the dynamics of trust and protection in a world where the supernatural is ever-present.