A perverted father who has been training his real daughter Lala (142 cm, shaved) with twisted affection now sets his sights on his niece Yuka (136 cm, shaved), whom he will be taking care of during summer vacation. He orders Lala to show her stepsister how to please him. Nervous Yuka, who was once close like sisters with kind-hearted Uncle and Lala, fears their abnormal incestuous relationship... Her innocent body resists at first but soon finds itself being trained, eventually begging for cocksucking, swallowing cum, and anal penetration. And then... As if it were natural, the two cousins begin pleasuring each other while serving their "uncle" together. Note that the contents may vary depending on the distribution method.