Naughty Little Junior Sister and Reliable Senior Brother

Four thousand years ago, the last city lord of Xuhuang City stood in front of the city gate, looking at the petrified people all over the city. "I want to find the answer." He said to the old man guarding the city. "If I can't come back, someone will come to replace me." He stepped out of the city gate and never came back. Four thousand years later, a girl with a ponytail bought the first jade slip at a secondhand stall in the market at the foot of the mountain. ——The gears of fate begin to turn.