Doctor Shin Sung-min is enraged upon learning that his daughter Jin-sook was murdered by a mentally unstable person while his wife Hwa-ja was with their colleague, Dr. Park Dong-won. Meanwhile, the perpetrator Heo Dal commits suicide out of guilt for killing Jin-sook, whom he considered his own daughter. Unaware of this, Sung-min adopts and raises Soo-jin, Heo Dal's daughter, from an orphanage. Sung-min develops growing affection for Soo-jin as she grows up, but his wife Hwa-ja mistreats her. Jin-young, Sung-min and Hwa-ja's son, falls in love with Soo-jin and overhears his parents' conversation, thus discovering that Soo-jin is the daughter of the man who killed his sister Jin-sook.