Modern engineer Shen Zhao traveled through time and became a border postman, secretly turning the tide of the war by improving beacon fire and firearms; secret agent Zhao Yan pretended to be a doctor and dug deep into the shady story of the court. When Han Lie's army rations were intercepted, the catkins' secret passage was investigated, and Ajie's life experience was exposed, the three of them joined forces to uncover Cui Yuanbai's shocking conspiracy in colluding with foreign enemies. The beacon smoke has not yet extinguished, the court is in chaos, and the drawings of a postman are burning through the foundation of the empire.
