Lin Bei, a graduate student in history, travels through time to the Jing Dynasty. Armed with knowledge of future wars, he starts with just four taels and eight qian of silver. He improves armor linings and establishes military supply production and transportation networks, helping the defenders of Changping Pass repel the Northern Di. He then joins forces with soldiers, merchants, and female workers to reorganize border military funding and promote reforms to the military recruitment system, gradually transforming military affairs and people's livelihoods across the northern frontier and even the southwest. Along the way, he and his companions turn barren wastelands into fertile farmland, giving more people land, dignity, and a new life.