The story begins at the Great Wall in the north of the Great Zhou Dynasty. General Lu Yuanzheng was accused of treason and died on the battlefield. News came back that his wife Shen Yuan was facing a desperate situation where her husband's family would break off the engagement, the court would interrogate her, and 30,000 "rebels" would be deported and used as slaves. In order to preserve the last blood and reputation of her deceased husband, Shen Yuan relied on the military strategies she had learned from her father (former Minister of War) since childhood and her thorough knowledge of the terrain in the North. She forged tokens and assumed the identity of a "distant cousin", and stepped into the crisis-ridden military camp with a weak body. Starting from the lowest level of the Huotou Army, she gradually used her extraordinary resourcefulness to solve crises such as food shortages, traitors, and morale disintegration in the army. She first showed her talents in an ambush battle in which a small number defeated a large number, attracting the attention of the supervisory army, the regent Xiao Yan. Xiao Yan was sent to purge the "rebels". He was cold and suspicious. At first, he regarded Shen Yuan as an opportunist, testing and suppressing him at every turn.
Shen Yuan has to deal with the scrutiny of Xiao Yan and the contempt of the military veterans inside, and fight against the elite cavalry of the enemy Huns outside. She used modern tactical thinking (not time travel, but based on the ultimate deduction of ancient military tactics) to invent sand table simulations, improve catapults, and set up special scouts. She often made unexpected plans, and successively achieved astonishing achievements such as "3,000 to 50,000", "Burning Battalion", "Securing the Pass on a Snowy Night", and gradually won over the hearts of the army and became the true soul of the Northern Army.
