Sumire, who lost her husband, ended up living with her daughter and son-in-law. It's a harmonious cohabitation life, but Sumire had one worry. It was her daughter and son-in-law's nightly activities. It's good that they get along well, but Sumire could only feel frustrated every night when she heard her daughter's voice of joy, and she was spending nights comforting herself alone. Sumire was curious about her son-in-law's lower body, which satisfies her daughter every night. One day, when her daughter went out, she peeked into her son-in-law's room and found him masturbating. Sumire entered the room, calmed the flustered son-in-law, and then, even though it was in the middle of it, she said "I'm sorry" and reached for her son-in-law's lower body…