Because the frail Sun Yi (Bo-yeong Park) needed to recuperate, Sun Yi and her two daughters moved from Seoul to a villa in the countryside. When cleaning the house, Sun Yi accidentally found the wolf boy (Joong-ki Song) left by the mysterious former owner Dr. Park in the warehouse. Sun Yi's mother took in this wolf boy out of kindness and named him Cheol-soo. In this way, the four of them began to live under the same roof. Sun Yi was initially disgusted with this intruder who could not speak and ate voraciously, but the daily interactions gave Sun Yi the idea of taking care of and training Cheol-soo. She began to teach him to eat, read, recognize words, and play guitar for the wolf boy. Cheol-soo was very useful to Sun Yi's warm care and did what Sun Yi taught him seriously. The lonely Sun Yi was happy because Cheol-soo gradually integrated into her world and developed a different love for him. However, this beauty was broken by Ji Tae (Yeon-Seok Yoo), who was eyeing the wolf boy. He was determined to gather and instigate various forces to kill Cheol Soo. In order to protect Cheol Soo, Sun Yi had to face the reality of separation from the person she loved. This film is the first commercial film debut of director Zhao Chengxi.