Sad Cypress recap

Elinor Carlisle and her fiance Roddy Welman visit their invalid aunt Laura at Hunterbury after an anonymous letter warns that the lodgekeeper's daughter, Mary Gerrard, is gaining influence over her. Roddy falls in love with Mary, ending his engagement. Laura dies without a completed will, and Elinor inherits, later making a generous settlement on Mary. At a lunch prepared by Elinor, Mary dies of morphine poisoning, and Elinor is tried with motive, opportunity, and poison all pointing toward her. Dr Peter Lord asks Poirot to investigate. Poirot shows that Nurse Hopkins put morphine in the tea, then used an emetic injection to protect herself. Hopkins had sent the warning letter and was positioned to inherit money Mary left to a relative. Elinor is acquitted; Peter admits that he invented evidence in an attempt to help her, but Poirot's real solution stands. Roddy belongs to Elinor's past, while Peter may belong to her future.

Elinor Carlisle and Roderick 'Roddy' Welman are engaged and expect one day to inherit from their wealthy aunt Laura Welman of Hunterbury. An anonymous letter warns that Mary Gerrard, the lodgekeeper's daughter whom Laura has educated and supported, is persuading the invalid woman to favour her. Elinor and Roddy visit. Laura has suffered a stroke and is attended by Dr Peter Lord, Nurse Hopkins, and Nurse O'Brien. Mary returns from training abroad, attractive and no longer comfortable in the social place assigned to her. The warning may be malicious, but it has identified a real tension around Laura's money and Mary's uncertain standing.

Roddy becomes infatuated with Mary, and his engagement to Elinor breaks under the strain. Laura Welman tries to communicate wishes about her estate but dies before a new will can be completed. Because she dies intestate, Elinor inherits as next of kin. Questions remain about medication in the sickroom and about what Laura meant to arrange for Mary. Elinor conducts herself with outward control despite losing both her aunt and her planned marriage. She decides to sell Hunterbury and makes a substantial financial provision for Mary, an action that is generous but also closes the household in which their lives have become entangled.

As Hunterbury is cleared, Elinor prepares sandwiches for a small lunch with Mary and Nurse Hopkins. Mary eats and soon collapses, dying from morphine poisoning. Elinor had access to morphine from her aunt's sickroom, prepared the food, and had been displaced in Roddy's affections by the victim. Her composure after the death is interpreted as coldness rather than shock. The police build a direct case: opportunity, means, jealousy, and the fact that the other person sharing the meal was not poisoned. Elinor is arrested and sent for trial. Peter Lord, who has developed strong feelings for her, refuses to accept that the visible explanation is the true one.

Peter Lord asks Poirot to examine the case. Poirot makes clear that affection is not evidence and that he will investigate Elinor as seriously as anyone else. He reconstructs Laura Welman's final illness, the medicines in the house, Mary's background, the anonymous letter, and the lunch. The prosecution theory places the poison in food prepared by Elinor, but Poirot tests every item eaten and drunk and asks how one diner could be poisoned while another remained well. He also explores Mary's family connections and the disposition of the money Elinor gave her. Several witnesses offer strong opinions about class, jealousy, and character; Poirot separates those judgements from what each person actually saw.

At trial the case against Elinor appears formidable. Witnesses establish her access to morphine, the broken engagement, the preparation of the sandwiches, and Mary's death soon after the meal. The defence can raise questions but cannot explain the entire sequence. Poirot follows details that do not fit: the precise serving of tea, a small injury on a wrist that has been given an innocent explanation, the possibility of using a drug to empty the stomach, and the financial meaning of Mary's will. He also detects that Peter Lord, driven by desperation, has tried to create an alternative trail involving an unknown person near the lodge. Poirot rejects that false help and prepares evidence that can survive the courtroom without it.

Poirot identifies Nurse Hopkins as Mary Gerrard's murderer. The morphine was not in Elinor's sandwiches but in the tea. Hopkins then used an injection of apomorphine to make herself vomit, explaining why she survived the shared meal; the supposed rose-thorn mark on her wrist was the injection site. Hopkins had sent the anonymous warning that brought Elinor and Roddy to Hunterbury, knew the truth about Mary's family and finances, and was the relative positioned to benefit from Mary's will. She used the obvious jealousy between Elinor, Roddy, and Mary to construct a case against Elinor. Peter Lord admits that he invented evidence of another person's presence in an attempt to save the woman he loves, but Poirot had discarded that fabrication and solved the crime from the meal, the drugs, and the money. Elinor is acquitted. Her relationship with Roddy is finished, while Peter's devotion offers the possibility of a different future.

Poirot proves that Nurse Hopkins poisoned Mary Gerrard. The prosecution assumed the morphine was in the fish-paste sandwiches prepared by Elinor, but Hopkins put it into the tea and protected herself by using apomorphine to make herself vomit; the mark on her wrist, explained as a rose-thorn scratch, came from the injection. Hopkins had sent the anonymous letter that brought Elinor and Roddy to Hunterbury and had cultivated knowledge of Mary's parentage and money. She was the relative who stood to benefit under Mary's will, giving her a motive hidden behind the more visible triangle involving Elinor, Roddy, and Mary. The evidence also establishes that Laura Welman's death and the missing morphine supplied Hopkins with knowledge and opportunity, though Elinor's trial concerns Mary's murder. Dr Peter Lord admits that, desperate to save Elinor, he manufactured a line of evidence suggesting another person had been near the lodge; Poirot recognised the fabrication and found the real proof independently. Elinor is acquitted. Her attachment to Roddy is over, and Peter Lord's loyal effort leaves open a quieter future between him and Elinor.