Amu-chan is staying over at her older brother's house. She deeply cares for her brother but has a persistent problem with frequent urination and bedwetting, which she desperately wants to keep hidden. Wanting to fix this, she confides in Chiharu-san, her brother's wife. Kind and thoughtful, Chiharu-san comes up with a plan—she prepares a large supply of disposable diapers and decides Amu-chan must wear them throughout her stay. At night, Chiharu sneaks into the bedroom to check whether Amu-chan wet the bed. She discovers that she did, and quietly changes her diaper on the spot. The next morning, Chiharu assists her as they begin potty training together.