Marina once made the mistake of her youth by taking the name "Yuto." Her father disappeared before her eyes, and Yuto was sent to a children's welfare facility at an early age. As time passed, Marina and Yuto began living together again. Seeing Yuto, now fully grown into a man's body, Marina deeply loves him and seeks to strengthen their parent-child bond by building a relationship through sex education. The emotions and conflicts that arise during this process depict a new kind of relationship between parent and child.