20 years ago, her husband died in a traffic accident, and she raised Hajime on her own. After graduating from high school, Hajime didn't work and stayed at home all the time. I wanted to get him out at least, so I invited him on a trip to a hot spring. The mistakes of his mother that he carried with him from the past. Even if she regrets it, she can't make up for the past, so Mio devotes herself to forbidden incest along with her love for her son...