The stepmother went on a trip to the hot springs with her son, having grown tired of her old husband. This woman constantly thought about infidelity, but was afraid of being discovered by her husband if she went out to cheat. So she decided to have an affair with her husband's son. The two of them had had sex many times without being caught. Feeling bored from having sex at home, this woman invited her son to go on a trip to the hot springs for a change of scenery.