The protagonist, Chen Sanjin, is 26 years old. He opens an "old nail shop" at the edge of the city and sells longevity materials, paper binding, and rust nails. Three generations of ancestors were "nailmakers" who specialized in nailing soul-sealing nails on coffins. Nowadays, cremation has become more popular and there are fewer coffins. He mainly makes a living by "pulling out rusty nails" for people. When moving graves, lifting coffins, and reburying, the old soul-sealing nails will rust, and the old nails must be pulled out and replaced with new ones, otherwise the soul will be uneasy.
