The day my stepmother kissed me. Reiko was taken in as the second wife by her boss at work, but she was surrounded by an unloving husband and an unfriendly stepson, and felt lonely at home. One day, she was invited by a fellow housewife from the neighborhood, Lisa, to a suspicious party, where she accidentally meets her stepson. The two are shocked and clash, but when they realize that they are both human beings who share the same sorrow and pain, the distance between them shrinks rapidly, and they end up in an unforgivable relationship... The two seek each other to fill what is missing, and their connection becomes deeper and stronger through passionate kissing and sex...