Ren Muying (played by Tony Leung) is a single father who raises his daughter Ellen (played by Charlene Choi) by teaching piano. However, after his daughter was promoted to Band 5, she became more and more disobedient, which made Ren Muying very worried. Ellen has always felt that her father is very "sissy" and feels that even if she has any trouble, her father is unreliable. Ellen's classmates misunderstood that her father was a martial arts master-Mu Ye Feiying, and asked to be his master one after another. Only then did Ellen change her opinion of her father. But Ren Muying's skills, which were mistakenly thought to be unique skills, were just practiced while taking care of his daughter. The daughter began to feel that her father was old, but she still caused trouble everywhere, and was even held hostage by Mu Ye Feiying's enemies. In order to save his daughter, Ren Muying went to the place where his daughter was trapped alone...