For the reason of preparing for the university entrance exam, the younger brother was invited by his older brother's family to stay together for the convenience of studying and commuting. Here, he was taken care of very attentively and lovingly by his sister-in-law Hatano, but it was also because of this that gradually both of them developed feelings for each other. The moments when the husband was at work were the times when their illicit affairs occurred. It's a pity that the husband diligently works every day to earn money to support his wife and younger brother without knowing that both of them are putting a very big horn on his head.