ケンジは、彼女の母・保奈美の巨乳と色香に惹かれ、勃起が収まらないほど興奮してしまう。夫が単身赴任中で寂しさを募らせていた保奈美もまた、ケンジの若さに欲情し、彼の名を呼びながら自慰に耽っていた。その現場を目撃したケンジは保奈美に関係を迫り、二人は娘の目を盗んで背徳的な情事に溺れていく。一度は家庭を壊すことを恐れて拒絶する保奈美だったが、若く元気な肉棒の快楽には抗えず、禁断の関係を深めていった。

Kenji is captivated by the large breasts and alluring charm of her mother, Honami, and becomes so aroused that he can't control his erection. Honami, whose husband is away on a business trip and who is feeling increasingly lonely, is also aroused by Kenji's youth and indulges in self-gratification while calling out his name. Kenji witnesses this and forces himself upon Honami, and the two of them steal away from their daughter's watchful eyes and become engrossed in a forbidden affair. Honami initially refuses, fearing that it will destroy her family, but she cannot resist the pleasure of his young and vigorous penis, and their forbidden relationship deepens.