Koichi felt empty as he was constantly commuting back and forth from work to home, and one day while commuting to work, he was sexually molested by a woman... - Excited by the exciting pleasure I've never experienced before, I can't hold back and fuck her. - However, the other person turns out to be Akari, a female employee of a business partner. - Feeling vulnerable, Koichi ends up accepting the reverse sexual act on the train as he is told. - Koichi gradually becomes engrossed in the perverted and extraordinary life with his girlfriend who is smiling and openly blaming him...