Kasumi divorced her husband a year ago. The reason was that she loved her son, Satoshi, far more deeply than her husband. After the divorce, Kasumi continued living with Satoshi, no longer caring about her ex. The two constantly craved each other's bodies, building a warm and intimate relationship. Along the way, they began enjoying a special act—tongue kiss sex. It was their way of confirming their feelings and binding themselves even closer together.