Lin Jingwei, an expert in modern strategic logistics and special operations, accidentally traveled to the northern battlefield of Daxia in the cold weapon era due to an exercise, and became a soldier in the army of the daughter of a criminal. She rescued Prince Jing Xiao Jue at the Yanmen Pass battlefield. Although she was suspected due to her unknown origin, she relied on her professional military skills to point out loopholes in the defense line and temporarily modified the fortifications to repel Beidi. She then rectified the hygiene of the military camp to curb the spread of the plague, and exposed in public the conspiracy of the envoy sent by the prince to send moldy medicinal materials and military rations mixed with sand, gradually gaining Xiao Jue's trust. Lin Jingwei discovered clues that Prince Xiao Jing had treason with the enemy and joined forces with Xiao Jue to make a plan. First, he launched a surprise attack on Wolf Howl Valley, a grain point in Beidi Tun, to obtain more evidence, and then staged a drama in which the commander was seriously injured and the army was demoralized to lure the enemy into the situation. The Beidi army approached the city, and the prince's rebels also pretended to be reinforcements and attacked from behind. At the critical moment, Xiao Jue led the hidden ghost-faced cavalry to attack the rebels. The two sat side by side at the top of the city, determined to join forces to fight back, eliminate the traitors, and protect Yanmen Pass.
