Taichi is staying with his brother while studying for his university entrance exams, but he can't concentrate on studying because he's fixated on his brother's wife Sumire's slender body and plump ass. One day, he accidentally peeks at Sumire masturbating through a gap in the door. Having seen the whole thing, Taichi can't get Sumire's lewd bare ass out of his head, and the next day, when Sumire stands in the kitchen, he becomes aroused and attacks her. Sumire resists Taichi's rough thrusts, which she doesn't get from her husband, but gradually she becomes addicted to him...