It was difficult for the younger brother to see, or at least hear, the sounds and moans of his brother having sex with his wife every day.
Due to some problems related to personal living expenses, Kata had to stay at his brother's house for a while before he could afford to take care of his own life. Living at his house is free, so Kata will save a good amount of money. But the boy also paid an equally high price, he was "attacked" by their eyes and ears, after all, he was a man, so no one could bear such a situation???. Thinking that this "torture" would last until I moved to another place, I didn't expect Kata to be able to do it again... secretly fucked his sister-in-law.
Hatano actively tried to cheat on her brother-in-law, perhaps she was too bored with sex with her husband so she switched to... seducing Kata.
Instead of Kata squeezing his cock and watching his brother and his wife have sex together, the young man is now the main character, although he is a little nervous, afraid that his brother will find out, but perhaps the younger brother will not refuse the priceless "gift" of his sister-in-law for himself.