美しく優しい人妻・真希は、優秀な夫の優吾と、浪人中の甥・春斗と3人で幸せに暮らしていた。しかし…この夫婦は1つ大きな問題を抱えていた。SEXが下手過ぎる旦那＋超絶マ・グ・ロな真希。ある日、その様子を春斗が目撃してしまい、真希のマグロっぷりに強い衝撃を受ける。素人童貞だが、デカチンと風俗で培ったテクニックで自信があった春斗は自分なら真希を満たせるのではと考え真希の唇を奪い行為に臨むのだが…想像を超えるイキっぷりに…。

Maki, a beautiful and kind married woman, lived happily with her accomplished husband, Yugo, and her nephew, Haruto, who was studying for his university entrance exams. However, this couple had one major problem: her husband was terrible at sex, and Maki was incredibly unresponsive. One day, Haruto witnesses this and is shocked by Maki's lack of sexual responsiveness. Although he is a virgin, Haruto is confident in his large penis and the techniques he honed at working in the sex industry, and he thinks he can satisfy Maki. He kisses her and tries to have sex with her, but she climaxes in a way that exceeds his imagination…