My sister ran out of the house after fighting with my mother. The cause of the fight was her new boyfriend... I let her stay the night with mixed emotions. I don't know where to look at my sister's defenseless appearance as she calmly changes her clothes in front of my brother, but the two of us sleep in the same futon. The brother is unaware of what's going on and is tormented by himself... He can't control his growing fantasies and Kokoro towards his boyfriend who plays with his sister's body as he pleases, even though he thought she was still a child until recently, and he loses himself and rapes his sister.