But his carefree life gradually ends when his brother, who has been married for a long time, suddenly returns. Because she had just given birth to her second child, her sister returned to her parents' house to easily raise the child, while her father-in-law stayed at his old house because of work. While he was at home, his second sister always exposed her big, round, plump breasts in front of him, wearing nothing but T-shaped underwear, making his entire body clearly visible. When they drank together, he deliberately teased her by daring her to drink his milk. But suddenly Taku agreed, but before he could back down, his sister had to give him milk. Taku often used her hands to move her breasts before breastfeeding, causing her sister's milk to flow. To take revenge on Taku, his younger sister who also "sucks milk", Taku also quickly succumbed to his second sister's charm and produced "milk". But how can you end this? He forced the second sister to kiss him. Even though she protested, he continued to kiss her, pulling her clitoris closer together. And begins their terrible relationship. Some time later, her second sister became pregnant. Because at this time she also had sex with her husband's brother, she didn't worry and could continue this bad relationship with him …