What about It’s not my family yet! Min-joo lived alone with her mother without her father. One day, my mother introduces a person who will become my step-dad. And even his new brother... After a while, Min-joo lives with his mother at his step-dad's house. She tries to release her confused mind through sex with her boyfriend, but her mind is still empty. However, Min-ju, who was increasingly attracted by the warm heart of her new brother who lived with her, He stretched out a hand of temptation to tell him the sex, The two gradually develop into a relationship more than a sibling...​