The murder of Ma Dayuan is the hidden crime at the center of A'Zhu’s interrogation of Madam Ma. By tracing an old Mid-Autumn gathering and the testimony of people who knew of it, A'Zhu challenges the prevailing suspicion of Xiao Feng and the Murong family; the inquiry then exposes the identity of the protected “leading big brother” as Duan Zhengchun, revealing the political stakes that had helped keep the killer’s name concealed.

The inquiry reopens the case

A'Zhu approaches Madam Ma with an offer framed as recognition: she says that she and Elder Wu have recommended Madam Ma for an elder’s position in the Beggar Society. She adds that Madam Ma’s advice could help capture Xiao Feng, then introduces a more urgent reason for the visit: information about Ma Dayuan’s murder. The flattering proposal gives A'Zhu a way to raise the case while watching Madam Ma’s response.

A'Zhu attributes the new lead to Zhao Qiansun, whom she says she met at Elder Xu’s memorial ceremony in Weihui. According to her account, Zhao claimed to know who had really killed Ma Dayuan. When A'Zhu specifies that the killer was neither Xiao Feng nor the Murong Clan of Gusu, Madam Ma reacts with anger and alarm. The contrast between her indifference to the elder proposal and her distress at the murder allegation makes the subject’s significance plain without yet establishing who committed the crime.

The Mid-Autumn gathering

A'Zhu says Zhao connected the murder to the eighth month of the previous year. Before she can finish, Madam Ma faints; after A'Zhu revives her, she explains that Zhao had described a Mid-Autumn gathering at the house of the “leading big brother.” Present were Grandpa Tan, Granny Tan, and the person Zhao called Ma Dayuan’s murderer.

The gathering is a clue, not a direct identification. A'Zhu reports that Zhao would not name the killer because he feared implicating Granny Tan, his former lover. Granny Tan, she says, confirmed that Zhao’s account of the gathering was correct, while Grandpa Tan responded angrily and refused to tell her the truth. With Zhao dead and the Tans unwilling to identify the person, A'Zhu says she will have to ask the “leading big brother” himself—even though she claims not to know who he is or where he lives.

This account overturns the public direction of suspicion. Xiao Feng and Murong Fu have been blamed, A'Zhu says, while the real killer remains free. Her appeal to the injustice done to Ma Dayuan gives the investigation a moral urgency: the dead man’s name, in her telling, cannot be cleared while attention remains fixed on the wrong suspects.

The protected identity exposed

Madam Ma recognizes that A'Zhu’s story is a tactful attempt to learn the “leading big brother’s” identity. The conversation shifts when Madam Ma invokes the Purely Yang Finger, associated with the Duan family, and challenges Elder Bai to infer the connection. A'Zhu answers that the ruling clan of Dali has long had little contact with the Central Plains martial world, an objection that prompts Madam Ma to distinguish the emperor from other members of the family who had travelled north.

Madam Ma identifies the “leading big brother” as Duan Zhengchun, the South-Stabilizing Prince and younger full brother of Dali’s emperor. Xiao Feng, listening, recognizes this as the name he has been seeking for months. The revelation ties the inquiry into Ma Dayuan’s murder to the broader search for the man associated with the Ambush at Yanmen Pass: Duan Zhengchun’s identity is not merely a private secret but a link between the Beggar Society’s old account of the ambush and the present investigation.

Madam Ma explains why Duan Zhengchun had been involved in affairs of the Central Plains despite his high position in Dali. She says that Elder Xu had described the prince as a guest at the Beggar Society’s headquarters when news arrived that Khitan warriors were heading toward Shaolin to seize scriptures. Out of honor, Duan Zhengchun led the party to intercept them outside Yanmen Pass. Though the deed was undertaken in the name of Great Song, Madam Ma argues that it also served Dali: if the Liao Empire conquered Great Song, Dali could be threatened next. She recalls Duan Zhengchun as young, skilled in martial arts, benevolent, generous, and second in rank only to the emperor.

Secrecy and political danger

A'Zhu draws the implication aloud: the “leading big brother” is the South-Stabilizing Prince, and people have refused to name him in order to protect him. Madam Ma insists that the disclosure must go no further. She invokes the deep friendship between Duan Zhengchun and the Beggar Society and warns that exposure could bring disaster. In her view, Xiao Feng might wait years for revenge, making the revelation a danger to Duan Zhengchun as well as a breach of the Society’s ties with Dali.

Madam Ma asks “Elder Bai” to swear secrecy. A'Zhu’s oath is carefully worded: it places the threatened punishment and loss of reputation on Bai Shijing, rather than on A'Zhu herself. The exchange shows that the disclosure has been extracted through a performance of compliance, not a straightforward confession. It also leaves an important distinction intact: Madam Ma reveals Duan Zhengchun’s identity as the “leading big brother,” but the account presented here does not name Ma Dayuan’s killer.

Significance of the revelation

The murder inquiry operates on two levels. Its immediate question is who killed Ma Dayuan, and the reported gathering narrows the trail to someone present at the “leading big brother’s” home. Its wider consequence is to expose the identity behind that title and explain why the name was guarded: Duan Zhengchun’s relationship with the Beggar Society and his role in the earlier confrontation with Khitan forces give the secret political weight.

The scene also complicates the pursuit of justice. A'Zhu challenges the ease with which blame has settled on Xiao Feng and the Murong family, but she must use disguise, insinuation, and a false promise of secrecy to obtain the next lead. The inquiry advances by revealing who was protected and why, even as the murderer remains unnamed in this exchange. That gap keeps the central crime unresolved while making the cost of its concealment newly visible.