In the third year after the apocalypse of the Dajing Dynasty, Shen Yan, a minor official in Yunmo County on the border, discovered a "30,000 stone gap between the book and the actual amount" when he was responsible for counting the border grain. As soon as he was about to report it, he was framed by the county magistrate and charged with "collaborating with the enemy to steal grain." His family was put on death row. Late at night, the old jailer who had been favored by the Shen family secretly let him escape. Before leaving, he gave him a bronze box and said only, "This is a relic of the former Taifu. It was entrusted to the Shen family for safekeeping. Now it is the only one that can save your life." Shen Yan opened the box and found that inside was the "Secret Volume of Mountains and Rivers" which recorded "the distribution map of the secret military sources of the previous dynasty" and "the locations of seven underground granaries".
