Plot

A rebellious young woman encounters a compassionate teacher whose impact motivates her to transform her life, aspiring to become a neurosurgeon.

Hye Jung is an uncivilized 16-year-old girl who finds her life miserable and nothing worth living (her mom died when she was little), so she never tries in school and always acts impolitely and violently towards others. Her father leaves her for her grandmother to take care of her. Until she accidentally bumps into a man (Ji Hong) while she steals a CD, and later he moves in her grandmother's house and becomes her teacher at school, her life has completely changed. He discovers that she is intelligent and he tries to keep her back on track. Her grandma wants her to have a good career, and she now believes in her successful future, so she tries to achieve her dream of being a doctor.

Yoo Hye Jung (Park Shin Hye) was a tough bully in school with a prickly personality and always goes wayward. She had many scars from her childhood and through self-preservation, Hye Jung keeps her heart shut away from other people. However, she changes after meeting her mentor Hong Ji Hong (Kim Rae Wong) who plays a key role in transforming her life from a helpless gangster to a compassionate doctor.

The right mentor can determine if you go to jail or achieve something greater in life. Yoo Hye Jung (Park Shin Hye) has had a tough childhood and difficult life. She has dealt with the life challenges by becoming emotionally guarded and acting like a tough bully at school. When Hong Ji Hong (Kim Rae Won) meets Hye Jung, he recognizes her intelligence behind her gangster facade and sets her on a path to become a compassionate doctor. Now a doctor in a neurosurgery residency at a major hospital, Hye Jung works alongside fellow residents Jung Yoon Do (Yoon Kyun Sang) and Jin Seo Woo (Lee Sung Kyung). But when Seo Woo becomes Hye Jung's biggest rival both professionally and personally, can Hye Jung overcome yet another major obstacle to her own personal happiness?

Yoo Hye-jung (Park Shin-hye) was a headstrong girl in high school with a prickly, gangster personality. Due to her many childhood scars, Hye-jung keeps her heart closed towards other people. However, she changes after meeting her mentor Hong Ji-hong (Kim Rae-won), who plays a key role in transforming her life from a "hopeless" delinquent to a compassionate doctor. They part ways due to a report of their close relationship, which was reported by a fellow student but subsequently meet again after 13 years, when Yoo Hye-jung had become a successful doctor.