The protagonist discovers an elderly woman living alone in a notorious garbage house, a residence so filled with clutter and refuse that it has become a point of shame and isolation for the neighborhood. The woman, whose name is gradually revealed to be Hanako, is a former professional cleaner who became unable to maintain her own space after a personal tragedy. Her only companion is a small, meticulously groomed toy poodle named Lemon, whose pristine condition contrasts starkly with the filthy surroundings.

The narrative follows the unnamed narrator as she begins visiting the house, initially out of concern and a sense of social obligation. Through these visits, she learns that Hanako is not merely lazy but suffering from a severe hoarding disorder triggered by grief and loneliness. The toy poodle serves as the emotional catalyst, forcing both women to confront the state of the home. Lemon needs walks, fresh water, and space, and caring for the dog becomes the first structured activity that pulls Hanako back into a routine.

A central arc involves the slow, painstaking process of clearing out the house. The narrator helps Hanako sort through mountains of old newspapers, broken appliances, and unopened mail, uncovering forgotten photographs and mementos that explain the source of her trauma. The clutter is not just trash but a physical manifestation of unresolved loss. A notable turning point occurs when Lemon falls ill from ingesting something toxic hidden in the debris, forcing Hanako to accept outside medical help and finally break her isolation.

The setting is a typical Japanese residential neighborhood where the garbage house is a silent eyesore, contrasting with the manicured gardens of the other residents. As the story progresses, the space transforms from a tomb of memories back into a home. The relationship between the narrator and Hanako deepens from caretaker and patient to a genuine found family, with Lemon acting as the constant thread of warmth and urgency. The narrative concludes with the house fully restored and Hanako re-entering community life, symbolized by her walking Lemon in the park without shame.