再婚し嫁いできた綺麗で優しい母、涼子。新しい家庭には大学浪人中の義理の息子がいる。夫は仕事が忙しく不在がち、義理の息子のほうに意識がいく涼子だった。息子とはいえ年齢も近く、息子のほうでもムチムチ女盛りの涼子を意識していたため、お互いドキドキする関係だった。そんなある日、息子の先輩が訪ねてきた。あいにく息子は不在でリビングで待ってもらうが、涼子はその友人に欲情を感じてしまう。冗談で誘惑しているうち、一線を越えてしまう。後日、味をしめた先輩はもう1人の友人を連れてSEX目的で遊びに来る。涼子はその2人とのプレイを楽しみ、とうとう息子とも・・・。Ryoko is a beautiful and kind mother who has remarried and married into a new family. In her new home, she has a son-in-law who is a university student. Her husband is busy with work and is often absent, so Ryoko's attention is focused on her son-in-law. Although they are sons, they are close in age, and Ryoko's son is also conscious of Ryoko, who is in the prime of womanhood, so their relationship is very exciting. One day, her son's senior came to visit her. Unfortunately, her son is not home, so she asks him to wait in the living room, but Ryoko feels lustful towards her friend. She jokingly seduces him and crosses the line. Later, the older man gets a taste of her and comes to visit her with another friend for sex. Ryoko enjoys playing with the two friends, and finally with her son...