Her name is Sun Yan, and she was born into the Sun family, which has been running martial arts schools for generations. But the traditional Sun family has always only had boys, not girls. In order to save her, her mother teamed up with her friends to transform her into a "boy". Everything was concealed very well at first, but unexpectedly, the family who had arranged to marry her many years ago suddenly came to find her. Not only did it catch her and her mother off guard, it eventually made her choose to go to an all-male university to delay the exposure of her identity. After arriving at the boys' school, life was not only not peaceful, but also full of challenges and mysteries. The mysterious roommate, the brother of her fiancée, the class boss who dislikes her, the acquaintance who knows her identity as a girl, and the strange female instructor. . . And every incident that happens will eventually involve her. What's even more incredible is that she gradually discovered that there seemed to be another 'Sun Yan'. Sun Yan felt that she was starting to become strange. Some inexplicable memories and some familiar pictures confused her. What happened? What's going on here?