The drama is adapted from the novel "I Have Three Dragon Childhood Sweethearts" by Yidai Xue and tells the story of a young girl named Nanyan who enters the world of immortals to save her mother and accidentally forms a fateful bond with a "heart lock." The story revolves around Nanyan, a skilled doctor who is forced to embark on a journey in the world of immortals to save her mother. Through a series of coincidences, she forms a mystical connection called the "Spiritual Connection Seal" with the enigmatic Emperor Ji Yang, who conceals his true identity. Nanyan is practical and down-to-earth, while Ji Yang is aloof and mysterious, embodying the essence of a true immortal. Initially, the two dislike each other, but as they investigate Nanyan's mother's illness, they become entangled in a conspiracy within the world of immortals.