My sister has become a gal

Your kind and serious sister. One day, the older sister, who has lived with her for so long, suddenly becomes a complete gal, both physically and mentally, after suffering a broken heart. Then, when her sister has lost her stump, she shows her sexual desire for you, which she has been holding back, and begins to attack her, and begins a harsh life of having sex all the time. *This work is equipped with a "flashback system" in which memories of a kind older sister who was raped by a gal sister are cut in through footage.