On the eve of the Anshi Rebellion, the mountains and rivers were about to collapse. Geological team member Zhang Xiaofan traveled through time and became the meanest postman on the border of the Tang Dynasty, with no system, no supernatural power, and no foresight. His only reliance is modern geographical thinking and a mind that knows the way. When the empire's post road was blocked by conspiracy and war, he took up the last letter that no one dared to send and turned around to step into the flames of war and snow.
