A mother named Yukari has raised her son alone since he was young, and now that he's found employment, she feels an overwhelming sense of accomplishment. Four years ago, they made a promise to have sex just once... ever since then, her heart and body have ached with longing. When her son invites her on a hot spring trip out of gratitude, she accepts eagerly despite knowing their past cannot be forgotten or forgiven. As they embark on this forbidden journey together, a new taboo relationship begins to blossom between mother and son... This is a story about incest!

ゆかりは息子を女手一人で育て、就職も決まった。四年前のある日一度だけとの約束で息子と関係を持っていた…。その日以来ゆかりの心と体はずっと疼いていた。ある日感謝の気持ちだと息子から温泉旅行に誘われて、二人きりでいくことにしたのだが…あの日の事が忘れる事の出来ない母は、ダメとわかっていても止まることが出来ない。母と息子の間に新たな禁断の関係が始まってゆく…近親相姦物語！