Incest mother-child favoritism

Yu has been a single mother for many years, raising her son Nobuo while working in the water business. Just when she was starting to feel tired of such a life, Fukasawa, a customer at the store, proposed to her and they decided to get married. And so, a happy newlywed life began. However, there was a side of her kind husband that was abusing her own son, Ma-kun. Yu feels sorry for him and ends up attacking him with her own body...and when Nobuo finds out...