A younger brother and his wife (Rio) who returned to their parents' home where a mother with dementia and her brother and wife lived in a legal affair. My brother's wife got tired of taking care of her mother half a year ago, and her brother had a desire. On the other hand, the younger brother and his wife are on good terms, but they are living a plain sex life, and Rio sometimes comforts himself. At that time, my younger brother returned to Tokyo for work. Rio will remain alone to take care of her mother.