Mariko decided to marry a man with a son who doesn't go to school. Yuusuke, her husband's stepson, couldn't recognize Mariko, his father's remarried partner, as his mother, and kept his distance even while living together. Mariko, who wants to deepen her relationship with Yuusuke, advises him that she wants to support him as a family member and as a mother, and Yuusuke gradually began to open his heart. However, Yuusuke's truancy remains unchanged, and Mariko is told that he failed in his relationships with women when she listens to his story. In response to Yuusuke's request to know a woman's body, Mariko gently guides him, saying, "Mommy will teach you, starting with an adult kiss..."
