Satomi, a stepmother, and her university student, Yuichi, live together in a house where her husband is working overseas. One day, Satomi witnesses her sleeping son's erect penis. Living away from her husband for a long time, she is helplessly drawn to her son's erect penis and finally crosses the line. Satomi takes the hard, throbbing penis into her mouth and devours it. With her husband away from home, the two of them can't stop living a naughty, lustful life.