Yang Liujiao is a widow from Suzhou who lives with her sister-in-law, Su Yugui, in the Su’s house. Tired of being alone, Yang has an affair with Qin Sanfeng, a secretary in the county government, and yearns to marry him. The two kill Sanfeng’s wife. They cut off her head and bury it under an aspen in the yard of the government office. Sanfeng dresses his dead wife’s body in Yang’s clothes and buries her headless corpse by a bridge. They throw a dagger into the grass to make it look as if Yugui murdered Yang.
The new District Magistrate, Meng, is fooled by the ruse and orders the execution of Su Yugui and her boyfriend, Liu. Zuo, the magistrate of Changzhou, learns about the arrest of his student Liu when he passes through Suzhou, and finds the case suspicious. Giving his official rank as a pledge, Zuo stops the execution and reopens the case, using the pair of embroidered red shoes found on the body as a clue. Yang flirts with the young and handsome Zuo, but he understands her true motives. Having established Yang as the real suspect, Zuo tracks down the skull and reveals the murderers. The sister-in-law and her boyfriend are freed then.