Chen Yuan and Zhao Zhipeng partnered to run a building materials warehouse, making an annual net profit of three million. However, Zhao Zhipeng made false accounts by fabricating losses and fake expenses, giving Chen Yuan only five thousand yuan, and secretly poached clients attempting to monopolize the business. Trapped in a debt crisis, Chen Yuan unexpectedly connected to the ancient Yunzhong Pass, transmitting modern building materials such as cement, steel, and insulation boards to help defending soldiers and civilians repair city walls, reinforce city gates, and build cold-proof warm rooms. He taught the skills of smelting and brick-making, encouraging the ancients to be self-reliant. In reality, Chen Yuan gathered evidence, exposed his partner's conspiracy, stabilized cooperative clients, and finally called the police to hand over Zhao Zhipeng, who embezzled the profits, for investigation.