Xie Yunfan, a tactical genius at the Modern Military Academy, accidentally fell into an ancient battlefield during a high-altitude parachuting training. When he woke up, he found that he had become a useless guard in Qingyun City, a small border town that was about to be surrounded by enemy forces. There are three thousand old and weak soldiers in the city, and outside the city is an army of fifty thousand cavalrymen who are watching eagerly. What's worse is that his immediate boss is a nerdy prefect who can only talk on paper. There is also a second-in-command in the government who wants to usurp the throne every day, and the court's food supplies are delayed. Everyone was waiting to see Xie Yunfan's joke, and even the people in the city were packing their luggage and getting ready to run away. But Xie Yunfan smiled - isn't this an upgraded version of a modern special operations exercise? So, a master tactician from the 21st century began his "dimensionality reduction strike" in ancient times: using physics knowledge to create mortars, using mine warfare to play with enemy supply lines, using electromagnetic principles to build an ancient version of the "radio communication network", and using psychological warfare to fool the enemy into doubting his life. While dealing with beauties from all walks of life, he built this dilapidated town into a fortress. While the big bosses in North Korea and China are still fighting for power, Xie Yunfan has already brought his "motley army" to give the world the most vivid lesson in modern warfare.
