A powerful demon master meets an innocent merman. Defying their fate to be enemies, the two share a magic journey and find soul mates in each other.

A powerful and talented demon master, Ji Yun He (Dilraba Dilmurat) has been blessed with a truly unique gift. Able to tame any demon, Yun He should have spent her life traveling the world, helping those who might be in need of her services. Alas, the strict laws laid down by imperial decree have confined her to the borders of Demon Valley. Unable to break free from the deep, dark secrets which keep her confined to the Valley, Yun He finds herself in a truly unexpected situation when she comes face to face with Chang Yi (Ren Jia Lun), a merman brought to the Valley by the cruel Princess Shunde (Guo Xiao Ting). Demanding that Yun He grant Chang Yi the ability to speak human words, grow human legs, and pledge undying loyalty, Princess Shunde expects Yun He to follow her orders without question. But to follow the princess's orders, Yun He would have to enlist the aid of her adopted brother and sworn enemy, Lin Hao Qing (Xiao Shun Yao), something she is loath to do. Forced together by an unusual fate, Yun He and Chang Yi draw inevitably closer. Realizing she has come to love him, Yun He refuses to bend Chang Yi's will to that of the Princess, but in giving him his freedom, will she be forced to sacrifice her own?.—Rakuten Viki