By chance, Xiao Wu stumbles upon a mysterious general store in the Yellow Springs and signs a life-and-death contract, becoming its night-shift clerk. From then on, he encounters eerie ghost customers every night, with even the slightest mistake putting his life on the line. Under the strict supervision of the shop owner, Luo Fei, Xiao Wu gradually learns secret arts of Yin and Yang, wielding a broken blade and a Han sword as he grows stronger through one life-threatening crisis after another. Meanwhile, a campus murder, complications involving his ex-girlfriend, and vengeful evil spirits seeking lives unfold one after another. The mysterious woman Bai Liuli and the red-clad vengeful ghost An Lin also become entangled in his fate. As bizarre incidents involving witchcraft, sinister formations, corpse curses, and nighttime coffin processions emerge, Xiao Wu begins actively breaking evil spells and investigating the mastermind behind them.