When the uncle returns home with his son, he is surprised at how much his niece has grown when they take a bath together that night. Her big, swollen breasts and the pubic hair growing between her legs... Ever since seeing her body, the uncle has become sexually aroused by her, and he ends up assaulting her in the middle of the night. After that, his son also starts to play pranks on his niece, and the father and son start toying with her together...