連れ子のいる男性と結婚し、三人での新生活を始めた茉莉奈。夫の連れ子・サトルは実母の愛を知らず、壁を作っていたが茉莉奈の母性に触れ、次第に心を開いてゆく。しかしある日、親子の距離感を知らないサトルに、接吻を求められる茉莉奈。不器用に、強引に唇を貪られ、茉莉奈は狂おしいほどに母性を刺激されてしまう。がむしゃらに激しいキスを迫るサトルを諭し、「お義母さんが、大人の接吻を教えてあげる」と優しく導いて…。

Marina married a man with a ***** from a previous marriage and began a new life with him and his son, Satoru. Satoru, who had never known his biological mother's love, had built a wall between them, but gradually opened up to Marina as he experienced her maternal warmth. However, one day, Satoru, unaware of the appropriate distance between parent and *****, asks Marina for a kiss. His clumsy, forceful kiss ignites a maddening surge of maternal feelings in Marina. She gently guides Satoru, who is desperately and intensely pursuing her kiss, telling him, "Your stepmother will teach you how to kiss like an adult…"