After dying, blacksmith Zhou Daniu arrives in the Underworld and is assigned as a clerk to the deserted Hall No. 7 of the Bing Division. Rather than blindly sticking to the rules, he uses his blacksmithing skills to befriend Ox-Head. Together with Sun Bu'er and Qian Duoduo, he organizes three hundred years of unresolved cases and reexamines wrongful convictions involving Meng Qiulian, Shen Mo, and others. Rising from a mere clerk to Director of the Review Office and eventually Master of the Review Hall, he investigates injustices, records merits, and brings a breath of fresh air to the Underworld.