The sister, a high school girl, is napping in her underwear with her panties exposed. Her brother, excited by his sister's scantily clad appearance, immediately grabs his penis for some self-pleasure. However, he is quickly noticed, and his sister labels him a pervert for his lustful thoughts. Yet, she gradually feels sorry for him. Despite her offer to help, the brother struggles to reach climax, leaving his sister exasperated...!