JUR-378 "My stepmother will teach you how to kiss an adult..." Furuto Mariko, a plump stepmother who takes away the lips and virginity of her unintentional husband's stepchild.

Mariko decides to marry a man with a son who is not attending school. - Yusuke, her husband's stepchild, is not recognized as her father's new wife, Mariko, and keeps her distance even while living together. - Tai Mariko, who deepens her relationship with Yusuke, advises her to support her as a family and mother, and Yusuke gradually begins to open up to her heart. - However, Yusuke's refusal has remained the same, and when he listens to her, Mariko is told that she has made a mistake in relation to women. - When Yusuke asks to know about women's bodies, Mariko gently guides Yusuke, saying, "Mom will start with the kiss of adults."