| | Character | Description | | :--- | :--- | :--- | | Lee Jong-suk | Park Hoon | A genius thoracic surgeon who was raised in North Korea and becomes an "outsider" after defecting to the South. His love for Song Jae-hee drives his every action. | | Jin Se-yeon | Song Jae-hee / Han Seung-hee | Park Hoon's first love from North Korea who mysteriously reappears in the South with a new identity and no memory of him. | | Park Hae-jin | Han Jae-joon | A highly skilled and ambitious surgeon at Myungwoo Hospital. He is Park Hoon's primary rival. | | Kang So-ra | Oh Soo-hyun | The daughter of the hospital chairman and a talented doctor. She becomes caught in a complicated love triangle. |

The series concludes with a reconciliation, showing Park Hoon achieving both his professional humanitarian goals and finding personal happiness.

This localization process enhances the viewing experience in several key ways: