After going to the city for a while, Koji decided to return to his hometown. He was told by his brother that his brother and sister-in-law, despite their efforts, were still infertile. Koji didn't pay much attention either, but he stumbled upon a scene where the two were having sex with each other. Jun seemed to see him too, but she was not panicked or embarrassed, but took the initiative to let him admire her body, exposing all her skills to him. Since then, Koji has not been able to take his eyes off his extremely charming sister-in-law. Jun really wanted to have a child, she secretly took her husband's sperm for testing and the result was that her husband's sperm was not healthy enough to get pregnant. She knew that no matter how many times she had sex with her husband, it would not work, so on the day of ovulation, she begged Koji to give her his sperm, extract all his sperm into her, and make her pregnant. Although he knows that this is incredibly wrong and a betrayal to his brother, Koji cannot resist his beautiful sister-in-law!