友達もいない地味中の地味子:松永が、ある日転んだところを助けてくれた普通の男に恋をした。しかし恋愛の仕方がわからず、根暗なアプローチとしてス○○カー行為を始める。その中で性癖が目覚め、勝手に家に忍び込み服を盗んでオナニーしたり、‘松永の中でだけ’は2人の仲は急速に深まって行く…

Matsunaga, a plain and unassuming girl with no friends, falls in love with an ordinary man who helps her when she falls one day. However, not knowing how to approach love, she begins a gloomy stalking behavior as her first attempt at romance. Through this, her sexual desires awaken, and she sneaks into his house, steals his clothes, and masturbates. In Matsunaga's mind, their relationship deepens rapidly…