Rise from the Dead, Defend the Lone City

In the seventh year of Chongzhen, heavy snow fell. Lu Yan awoke from a pile of corpses, descending into the chaotic Ming Dynasty, and unlocked a historical deduction panel. Deducting the battlefield, scanning hearts, all at a cost of real gold and silver. The city was plagued by pestilence, local gentry secretly colluded with bandits, and five thousand rebel soldiers were at the gates. With no elite troops at hand and no surplus grain in the treasury, he only had a bowl of hot porridge to gather the displaced people. He eliminated traitors within, repelled strong enemies without, forged firearms, promoted military farming, and with a lone city, protected thousands of lives. — Description from novelcodex.org