The family of four opens their eyes to find themselves time-traveled to a desolate mountain and a broken house, drafty with no food. Chemistry PhD Lin Bu'er is unfazed: leave three inches of stubble on the rice stalks to reap a free harvest of ratoon rice; boil plant ash for alkali, toss pork fat scraps into the pan, and the very first bar of soap is snatched up by the entire village. Starting from a single bar of soap—waterwheels spin, lotus ponds open up, coal mountains smelt iron, steam engines drive heavy iron hammers, driving all the way until the ironworks smoke. The wife manages the accounts, the son becomes a presented scholar, the daughter runs the soap workshop, advancing on three fronts, and they stubbornly turn the barren mountain into a county legend.