Hanako manifests as an imposing spirit exclusively visible to Kayoko, a housewife, in the story "Extra-Large Size Happiness". This large-sized entity remains undetectable to Kayoko's husband Ryūichi and her mother-in-law. Its persistent presence disrupts Kayoko's daily routines and household equilibrium. Hanako’s emergence coincides with the mother-in-law’s relocation into their home and her campaign for a larger residence. The spirit’s interference strains Kayoko’s relationship with her mother-in-law, who interprets Kayoko’s reactions as instability or disrespect. Tensions peak when Hanako physically obstructs Kayoko during a real estate meeting, thwarting plans to acquire a new property.

Hanako’s identity is unveiled as the spirit of Kayoko’s childhood dog, a companion during her isolated youth. The dog had been relinquished by Kayoko’s family after outgrowing their space and died in a landslide while attempting to reunite with her. Hanako’s lingering presence arises from an unbroken bond and protective devotion. Resolution occurs when Kayoko formally acknowledges their connection and affirms her current familial contentment. This reassurance permits Hanako to depart peacefully, dissolving household discord. Subsequently, Kayoko encounters a puppy mirroring her childhood dog, implying a cyclical renewal of their bond.