Kozue dotes on her son so much that before she knew it, they had become a couple. Now living apart, the two of them had been planning a trip to a hot spring just the two of them. It was supposed to be a rich time filled with lust for mother and son, meeting for the first time in a long time. However... When Kozue and her son arrived at the inn they were looking for, she immediately invited her son, who was trying to play with her body, to the open-air bath. The two washed each other's bodies in the open-air bath and played with each other. Gradually, they got excited, and Kozue took her son inside her and climaxed. As Kozue was walking down the hallway after spending a very satisfying time, she was suddenly stopped. The person who stopped her was a detective who had been hired by her husband, who suspected Kozue's affair. The detective grinned at the upset Kozue, and said, "I'll keep your wife a secret, so please listen to what I say," and he teased her, exposing her lower body and forcing her to take it in his mouth and splashing his milky liquid on her...