Frau Kobato, a doctor's wife and mother, relocates with her family to Toriai Mansion. As a new resident, she heeds neighborly advice to introduce herself to the influential Mrs. Shiratori ("The Queen") while being warned against associating with the elderly Mrs. Ukai ("The Witch") living above her. Her development starts when she aids the ill Mrs. Kamoshita, who is enduring a year-long cleaning duty punishment from Shiratori for failing to introduce herself formally. Kobato assists Kamoshita, disregarding potential repercussions. This act draws Shiratori's visit under false concern, where she again warns Kobato against Ukai and Kamoshita. Hearing noises from Ukai's apartment during this visit, Kobato investigates, finds Ukai injured, and overrides Shiratori's objections to call an ambulance, publicly rebuking Shiratori's callousness.

In gratitude, Ukai entrusts Kobato with her mynah bird, Kyū, hinting it might be useful. Shiratori retaliates by manipulating the management committee into appointing Kobato as the new cleaning duty replacement. Kobato endures Shiratori's excessive demands and refuses to apologize despite an anonymous call urging submission. When Kobato falls ill, Shiratori publicly accuses her of shirking duties. Kyū then utters "Kanishabu," visibly distressing Shiratori; Kobato misinterprets this as a magical deterrent.

After Ukai recuperates with her son, Kobato learns she must continue cleaning duties alongside Kamoshita. They develop solidarity, jointly resisting Shiratori's unreasonable demands. However, when Kobato asks Kyū aloud about "Kanishabu," Shiratori overhears and realizes Kobato doesn't know its meaning. Shiratori retaliates by sabotaging the communal trash site. Kobato's attempt to use "Kanishabu" fails, but Ukai intervenes, revealing it refers to crab, her favorite food. They deduce Shiratori stole and consumed a live crab intended for Ukai the previous year, causing Ukai's subsequent illness. Faced with exposure, Shiratori cleans the mess herself to prevent scandal. The conflict ends with Shiratori moving out, and Kobato, Kamoshita, and Ukai sharing a meal of crab.