Set during the reign of King Injong in the Joseon Dynasty, the story follows Choi Won, a royal physician who finds himself framed for the murder of a fellow doctor. Desperate to save his terminally ill daughter, Choi Won goes on the run, navigating a dangerous web of political conspiracies and palace intrigue. As he evades capture, he must uncover the truth behind the assassination plot to clear his name and secure the medicine needed to heal his child. Throughout his journey, Choi Won is aided by Hong Da-in, a royal nurse who believes in his innocence, and Lee Ho, the Crown Prince who is struggling to survive the treacherous power struggles within the court. The series blends historical drama with a high-stakes thriller narrative, highlighting the lengths a father will go to for his family while exposing the corruption that threatens the stability of the kingdom.