Mother Chiaki and her only son, Kenji, have a physical relationship because they can't stop bathing with their mother and child even after puberty. However, after Kenji became an examinee, he set a deadline "until he passed" and refrained from bathing together. And then came spring. Despite his efforts, Kenji fails the exam. Chiaki can't wait to see Kenji who doesn't feel like doing anything and is just lounging around at home.