Bong Woo-Ri (Kim Sae-Ron/Hwang Jung-Eum) was a bright 9-year-old girl, but she didn't have a name or a father. Her mother was also deaf. Nevertheless, there were good people around her like Bong Young-Gyu (Jung Bo-Suk) - a man who loved her mother and was also mentally deficient. The Young-Gyu lived with his elderly mother and his son Bong Ma-Roo (later played by Nam Gung-Min).  Bong Ma-Roo was an honor student who was insecure about his foul-mouthed grandmother and his mentally deficient father. To make matters worse, his father married a woman who was deaf. Meanwhile, 9-year-old Bong Woo-Ri was elated that she finally had a family and a name. Tragedy soon struck when a fire occurred in a factory where their deaf mother worked. Their mother died in the fire and their father was taken into police custody because of a frame-up . Ma-Roo left his sister and said he would come back. Now, Bong Woo-Ri, her grandmother and father awaited his return.  Meanwhile, Dong-Joo (Kang Chan-Hee/Kim Jae-Won) lived with his grandfather, mother and stepfather. His grandfather owned the company "Yoo-Kyung," but the company was run by the step-father due to the grandfather's bad health. By chance, Dong-Joo met Woo-Ri. He promised to teach her how to play the piano. To keep his promise, Dong-Joo attempted to sneak out at night once. During this time, he saw his step-father allow his grandfather to die. An accident then occurred that resulted in Dong-Joo permanently losing his hearing. At the funeral for his grandfather, Dong-Joo's mother learned that her husband cheated on her and even fathered another child. Dong-Joo's mother also learned that the other child was Bong Ma-Roo. The mother then hid Dong-Joo's loss of hearing and took him to live overseas. For revenge, Dong-Joo's mother also took Bong Ma-Roo with them. While living overseas, Bong Ma-Roo changed his name to Jang Joon-Ha. Dong-Joo also learned how to read lips and, because of this, could act as someone with normal hearing. Everything was set. The three of them returned to South Korea and Dong-Joo now attempts to return the company to his mother and exact revenge upon his stepfather ....