All the women grab for the papers, including the usually stoic Agatha. Dorothy chastises the women, reminding them that they can’t read May’s last words in public and that the document is worthy of respect, not excitement. The women ride silently to their hotel, where Emma arranges for them to dine in private and examine the letter. Satisfied that the women have calmed down, Dorothy begins to read the letter aloud to the others.

May’s letter confirms that she had an affair with an unnamed married man for six months before her death, that she was sexually assaulted, and that she was pressured into having an abortion. She refused to have an abortion. Shortly after, when she saw “familiar names” in a newspaper article about a missing violinist, she worried that her life was in danger. In Boulogne, a stranger approached her, offering to arrange the abortion. His odd behavior was so unnerving that she wrote the note in case anything happened to her, planning for Celia to retrieve it if necessary.

After finding the letter, Dorothy can’t sleep. Now deeply moved by May’s case, she’s embarrassed that she once considered solving this crime an adventure. In addition, she worries that even if she can identify the killer, the police won’t take her seriously. Hearing a sound in the hallway, Dorothy realizes that a man is attempting to enter her room. She screams and waves a pewter candlestick, scaring him off. Dorothy realizes that she’s being targeted.

Dorothy returns to London to find her flat exactly as she left it. However, she feels as if she has changed significantly since the attack, her time in Oxfordshire with Ivy and John, and the discovery of May’s letter. She tries to relax in the bath but grows anxious about the stack of letters awaiting her. She finds an envelope with no return address. Inside, an anonymous letter warns that news of John will spread unless she stops investigating May Daniels.

Dorothy notes that although the letter was written in blue ink, a more expensive option than typical black, it’s on cheap paper. She wonders if the letter was written by the same person who threatened May and worries that her family is in danger. Agatha stops in to check on her, and Dorothy reluctantly tells her about the letter and John. Agatha promises to keep her secret but encourages her to share it with the other women.

Agatha convinces Dorothy to join her and the other Queens of Crime at Simpson’s in the Strand, a luxurious and prestigious restaurant that, in the works of Sir Arthur Conan Doyle, was a celebration spot for Sherlock Holmes. The other women hint at a reason to celebrate, confusing Dorothy. Although they had no luck getting police to take May’s letters seriously, they have developed a plan to trap Louis Williams on their own.

The women reveal that Louis Williams is attending a dinner at Simpson’s that evening and that they plan for Margery to meet him at the bar and take him to a nearby hotel. Along with a Pinkerton detective hired as security, the women wait for Margery and Louis in the hotel room. After taking a photo of Louis and Margery kissing, they reveal themselves. Louis is shocked and confused, worrying Dorothy, who reasons that if he were responsible for the threatening letters, he would know who they are.

Louis insists that he had nothing to do with May’s death, Dorothy’s attack, or the attempted break-in in Boulogne. When the women read May’s letter, he’s shocked, claiming that he was never intimate with her and she never mentioned being pregnant. He explains that he reached out to May in October because he was lonely at home and missed her company. He hints that he might know who killed her.

Dorothy allows Louis to leave, infuriating Ngaio. When Emma defends Dorothy, arguing that detaining Louis illegally would tarnish their reputations, Ngaio accuses Emma of being cowardly. Emma retorts that Ngaio is rash and claims that she cares about her reputation only as a means of bringing justice to May. Dorothy argues that May’s letter doesn’t explicitly name Louis as her boyfriend or the father and suggests that they meet the following day to consider the mystery as writers.

The Queens of Crime escort Dorothy home to ensure her safety. Mac returns, and Dorothy partially reveals her work on the May Daniels case to him, framing it as a casual puzzle for the Queens rather than the dangerous investigation it is. Mac reveals that Jimmy Williams is connected to gambling and gangs and that Sir Alfred Chapman also has ties to criminal activity. Dorothy assures him that her activities are innocent and that she’s no threat to anyone.

When the women gather to discuss the case, Dorothy encourages them to think about it as if it were a fictional mystery they were constructing. She argues that as a writer, she’s at the service of the plotline: She writes around the mystery as it reveals itself rather than imposing her desires on it. Together, the women decide to use a mystery-novel classic scenario: a gathering of the suspects. They plan to bring Louis and Jimmy Williams together with Sir Alfred Chapman and watch their reactions to determine the killer.

The women trick Louis into arranging a meeting between his father and Sir Alfred Chapman, and the women then join the meeting. After the interrogation, Sir Alfred admits that he assaulted May Daniels when she came backstage to thank him (on Louis’s behalf) for the Cavalcade tickets. He implies that he also assaulted violinist Leonora Denning. Sir Alfred explains that he led Jimmy to believe that Louis had impregnated May, and the men conspired to kill her. Jimmy insists that he only wanted Sir Alfred to pressure May to have an abortion. Sir Alfred warns that if he’s arrested, he’ll take Jimmy and Louis down with him.

Before anyone can speak, Louis’s secretary, Miss Bennett (who came in when she heard shouting), interjects, addressing Sir Alfred directly. She claims that they were having an affair and that he used her to spy on Louis at Jimmy’s request and tricked her into helping him arrange the attacks on Dorothy. She denounces him as a manipulative liar who sees women as interchangeable and disposable. Furious at his betrayal, she pushes him down a flight of stairs, killing him. Dorothy considers it vengeance for May.

Jimmy insists that Miss Bennett be arrested for murder for pushing Sir Alfred down the stairs, but the Queens of Crime claim (as one) that they saw Sir Alfred fall. Dorothy tells Jimmy that he must tell the police the truth about Sir Alfred’s role in May Daniels’s death, including his role in connecting Sir Alfred with the murderer. Jimmy admits that his man followed May from Brighton to Boulogne and strangled May, causing her to miscarry. Dorothy warns that if Jimmy doesn’t go to the police, the Queens of Crime will use the evidence they gathered to pin the murder on Louis. Jimmy agrees.

The Queens of Crime and the other members of the Detection Club convene at the Savoy Hotel for a club meeting. A group of male members approach the women, asking them to join in a murder-mystery game and attempt to solve a fictional mystery. Agatha reminds them that they don’t solve fictional mysteries. The club’s president raises a toast to the women for solving the murder of May Daniels, leading to the sentencing of Jimmy Williams. He claims that the club is fortunate to have the women among its members. The women celebrate securing justice for May Daniels.