SONE-480 _Incest with a sister with big breasts and a different mother

Miyu Kiyohara suddenly has a brother? Oh no, that's a "Brother who surpasses a thousand prodigal sons" brought by his mother. Miyu's mother remarried a man who already had children of his own - Tatsuya. Being rebellious, Miyu doesn't like her seemingly dull brother, especially when he keeps staring at her huge breasts. Miyu and Tatsuya's family decided to go on holiday to Cuu Chan Island, but Miyu didn't like it so she stayed home. Tatsuya just realized that he forgot to bring a sweater that day, so he went home to get something and saw Miyu wandering around. He decided to go back and make evidence to inform his parents, but Miyu begged him to stop. How will Tatsuya decide to resolve this? Are you the chicken or the grain in this story? We invite you to watch!