Noboru decided to stay at his brother's house for the exam. Koyuki, the sister-in-law who was longing for her brother's words, taught her to study, but Koyuki's sigh and climbing on her chest inflated her crotch. One day, when Noboru sees Koyuki masturbating, he can't control his feelings. Then Koyuki gently guides Noboru's hand to her chest... After that, the two of them devoured each other every day, but suddenly the older brother who was supposed to have gone on a business trip came back.
