[My mother's boyfriend who suddenly rolled in was strangely sexy... ] Naoto, a student, has recently been in trouble. One day her mother suddenly brought her boyfriend, Izuna, who is living in her house. Naoto finds out that Izuna's occupation is an erotic novelist and imagines Izuna's erotic appearance. On top of that, Izuna was abandoned by her mother, and he said, "Naoto, be my lover!" ? Many times more erotic than I imagined, I was melted down by the technique of an adult... I'm going to insert it into Izuna's hot place...! Big brother is insanely erotic, it's not very much, but I can't beat it!