The series follows Hong Eun-jo, a noblewoman hiding her secret life as the righteous thief Hong Gil-dong, who steals from the rich to help the poor. She attracts the attention of Yi Yeol, a royal prince tasked with capturing her. As he closes in, their lives intersect when they unexpectedly switch souls, forcing them to navigate each other's worlds amidst the complexities of duty, identity, and forbidden love.