It's been six months since Yumi's son graduated from university and took a year off to find a job. He finally got a job, and thinking that they wouldn't be able to go on a trip together as a family of three, she planned a family trip. The atmosphere at the destination was different from usual, and her husband was more excited than usual, so he and Yumi had a passionate encounter at the hot springs. His son accidentally peeked on them. That night, the son couldn't sleep, excited by what he saw of his parents having sex during the day. The son sneaked into where his parents were sleeping, unbuttoned Yumi's clothes and began to lick her nipples. His hands then reached down below. Yumi noticed and tried to stop him, but...