Mitarai Shougo

He is a virgin boy who yearns for Shouko, one of his seniors. He has been a childhood friend of Shouko's younger sister, Marina, and has had a crush on her for many years since he first met her through Marina.

One day, he is pushed down on by Hijiri, who is drunk from a broken heart, and takes his virginity away from him. The first thing that comes to mind is the fact that the two of them have been in a relationship for a long time.

the midst of this, Shouko suddenly decided to join in.