The Su family has a daughter named Xiaoli, who can do anything. Unexpectedly, the crown prince ordered that the eldest son of the important officials in the city must enter the palace and be trained to be a sword-carrying guard. He must not leave the palace unless he dies. The eldest son of the Su family is weak and sickly, and cannot withstand the high-pressure training. Su Xiaoli, who learned about this, got her brother drunk overnight, disguised as a man and replaced him in the palace. In order to save her life, Su Xiaoli was very cautious. But when she saw her partner Xie Zihuai being bullied, she couldn't help but stand up. This also successfully attracted the attention of the crown prince Song Qiyuan.