When Koyama Kei was in elementary school, he lost his mother and never reconnected with his distant, workaholic father. The only bright spot in his home life is his sister Moe, a college student who adores him. However, Kei struggles with intimacy and even his sister can't sense it.
At 15 years old, Kei has never been in love but seeks physical gratification with anyone who shows him interest. He uses this distraction to forget the emptiness in his own life.
One late Spring day, Kei realizes what he has been missing: a slightly scatterbrained med-student named Fuji. Sadly, Fuji is his sister's significant other.
