I went to Tokyo to study for my entrance exams and ended up staying at my brother's house. When I got there, my brother wasn't there and my sister-in-law, Hikari, greeted me alone. She's always cheerful and kind, and a beauty that's too good for my brother... I've secretly admired her ever since I first met her. It turns out my brother is on a business trip for a week, so I'm left alone with my sister-in-law... Her breasts are even more beautiful with her revealing clothes, and seeing her defenseless makes it impossible for me, a virgin, to concentrate on my studies... And then, when my sister-in-law said, "This is just a rehearsal for when I get a girlfriend," I finally reached my limit... Oral ejaculation, creampie, facial... a total of 7 ejaculations. A 150-minute story of first time sex with the alluring and sexy Hikari Hime.