Yukari is raising her son on her own and has found a job. One day four years ago, I had a relationship with my son with the promise of just one time... Since that day, Yukari's mind and body have been aching. One day, out of gratitude, her son invited her to go on a trip to a hot spring, and the two of them decided to go on a trip alone...But the mother, who can't forget that day, can't stop even though she knows it's no good. do not have. A new forbidden relationship begins between mother and son...an incest story!