Kenji was struggling to live alone for the first time in a long time after seeing his wife go back to her hometown to give birth. Just when he was about to give up on the housework and cooking, his wife's sister Reiko came to help him with the housework. Kenji was exhausted from all the unfamiliar things, so he gladly welcomed Reiko, but... Reiko's real target was Kenji's penis. Not knowing this, he couldn't help but get a full erection when she boldly flashed her breasts and touched his body...