He transmigrates into a minor official in the Ministry of Works at the end of a dynasty. The moment he opens his eyes, he finds himself tied to a riverbank. The county magistrate downstream plans to sacrifice him to the river god. Floodwaters have already overtopped the embankment, and thirty thousand people are about to drown. Staring at the raging Yellow River, he hears a mechanical voice in his mind: [Civilization crisis detected: Yellow River flooding. Refinement Plan A: Reinforce the embankment with cement (requires 3,000 tons of limestone)... Plan C: Blast the upstream mountains to redirect the river (requires a black-powder formula).] He looks up at the county magistrate raising his blade and says, "Give me three days, and I'll change the Yellow River's course." The entire scene falls silent.
