Koji, who lives with his older brother and his wife, accidentally sees his sister-in-law changing clothes. His brother-in-law's eyes are burned into his sister-in-law's slender body, which makes him captivated and tormented. Unable to bear his forbidden desire, Koji steals Kana's underwear and indulges in masturbation... However, Kana finds him in the act... What action does Kana take at that time?