Zhang Hao, a modern urban white-collar worker, encounters a flash flood on a rainy night and accidentally travels to the 21st year of Wanli in the Ming Dynasty. The three ancestral sacred books he carried with him - "The Barefoot Doctor's Manual", "Militia Training Manual" and "Friends of Military and Civilian Talents" - became the key to changing history. While treating plague patients at the Chenghuang Temple, he met Zheng Lin Wanqing, a female doctor from the Imperial Hospital. The two discovered that each other was the inheritor of the "Qingnang Society" in the Jianwen Dynasty. The combination of the jade bracelet and the jade pendant in his hand could solve the mystery of time and space.
Relying on modern thinking and ancient strategies, Zhang Hao used the "Militia Training Manual" to improve the tactics of the Ming army and created the "three-stage strike" firearm formation. He also referred to the "Friends of Military and Civilian Dual-Use Talents" to develop advanced weapons such as poison gas bombs and multi-stage rockets. He led the three major battles of the Pyongyang Retrieval War, the Ningxia Rebellion and the Battle of Boju, and turned the tide of the Wanli War. He was involved in Zhang Juzheng's reform, designed the "One Whip Method" improvement plan, exposed the corruption of the Ministry of Industry and the Fujian kerosene smuggling network, and launched the "Qingnang Plan" intelligence secret war with Dongchang and Jinyiwei.
As a medical officer, Lin Wanqing established a secret intelligence network, used the "Barefoot Doctor's Manual" to improve ancient medical techniques, and designed a prototype "first aid kit". After being captured, he obtained the Japanese army's defense map through acupuncture. She exposed the corruption case in Suzhou Weaving Bureau, led the compilation of "Ten Tips on Epidemic Prevention", and finally discovered the connection between Emperor Jianwen's treasure and the star map of Zheng He's fleet.
