To protect her family's noble title, He Yan, the eldest daughter of the He family, is forced to don a mask and pose as the family's eldest son, "He Ru Fei." As a young girl, He Yan first meets the brilliant scholar Xiao Jue at Xianchang Academy. Determined to escape her family's fate, she leaves the academy and heads to the battlefield.
Years later, He Yan returns home as a celebrated hero, only to be betrayed by her family when her brother He Ru Fei reappears. Surviving the treachery, He Yan assumes a new identity as He Yan, the daughter of a city gate officer, and disguises herself as a man to join the military in Yezhou, vowing to reclaim everything that was taken from her.
In Yezhou, He Yan befriends the gentle and refined Chu Zhao and once again crosses paths with Xiao Jue. However, Xiao Jue suspects He Yan of being a spy and constantly tests her. Despite his suspicions, He Yan clings to Xiao Jue and proves her abilities by becoming the top soldier in Yezhou's defense force. Through various trials, including the Sun family incident, the Ji Yang Princess affair, and the battle to defend Rundu, the two face life and death together and gradually come to understand each other's true feelings.
