Dead Man's Folly recap

Ariadne Oliver asks Poirot to attend a fete at Nasse House because the murder-hunt game she has designed feels as if it is being manipulated for a real purpose. The girl playing the victim, Marlene Tucker, is found strangled in the boathouse, and Lady Hattie Stubbs disappears as her visiting cousin Etienne de Sousa arrives. Poirot eventually connects the crime to the history of the Folliat family and the folly built on the estate. Sir George Stubbs is really James Folliat, Amy Folliat's supposedly dead son. The real, wealthy Hattie was murdered, and another woman had long impersonated her; during the fete the impostor simply changed clothes and departed among the crowd. The real Hattie's body was hidden beneath the folly. Marlene had acquired knowledge that let her blackmail Sir George, so he killed her under cover of the staged game. Etienne's arrival threatened to expose the false Hattie. Poirot's solution leaves Amy Folliat confronting the cost of having protected her son and helped sustain his assumed identity.

Ariadne Oliver abruptly asks Poirot to come to Nasse House, where she has been engaged to devise a murder-hunt game for a charity fete. She cannot name a crime, but repeated suggestions and alterations by other people have made her feel that her fictional plot is being bent toward an unknown purpose. Poirot meets Sir George Stubbs, the wealthy owner; his beautiful young wife Hattie; and Amy Folliat, whose family formerly owned the estate and who now lives at its lodge. The preparations scatter volunteers, guests, and workmen across the house and grounds, creating a setting in which almost anyone can move without attracting notice.

On the day of the fete, visitors crowd Nasse House. Marlene Tucker waits in the boathouse to play the murder victim and reveal the final clue to contestants. Hattie Stubbs is disturbed by the expected arrival of Etienne de Sousa, a cousin from overseas whom she says she barely remembers. Amid games, refreshments, and tours of the grounds, Poirot watches private tensions beneath the public bustle. When the time comes to check the murder hunt, Marlene is found genuinely dead in the boathouse. The staged puzzle has given the killer a reason for the girl to be alone and for people to approach her without immediate alarm.

Inspector Bland takes charge of the crowded crime scene. Hattie Stubbs cannot be found, and her disappearance becomes inseparable from Marlene's death. Etienne de Sousa arrives by river and acknowledges that he has not seen his cousin since she was young, leaving uncertainty about what either would recognise. Witness accounts from the fete produce many movements but few reliable identifications. Marlene seemed an unlikely target, yet her appetite for gossip and small payments suggests she may have possessed information she did not understand. Poirot is dissatisfied with explanations that treat Lady Stubbs simply as another victim or as an impulsive fugitive.

The inquiry examines Marlene's family, including stories repeated by her elderly grandfather, and reconstructs which parts of the grounds could be watched from local paths and cottages. Alec Legge's secretive political concerns and his strained marriage to Sally form one line of suspicion, but they do not explain the design of Mrs Oliver's game. Poirot returns to Amy Folliat and the collapse of her family, including the sons she lost and her role in bringing Sir George and Hattie together. The ornamental folly, an expensive building with little practical use, increasingly matters as a feature imposed on ground with an older history.

Poirot keeps testing the apparent disappearance. A person in distinctive clothes can cease to be noticed simply by changing into the ordinary dress of the fete crowd, while a visitor who knew Hattie only long ago may still threaten a substitution. He concludes that Marlene's murder, Lady Stubbs's absence, and the Folliat past belong to one plan rather than separate events. The girl's knowledge came indirectly from things noticed by an older relative, turning gossip into a basis for blackmail. Poirot also becomes convinced that a death predating the fete is physically tied to the estate and that Amy Folliat knows more than she has admitted about the identity of its present owner.

Poirot identifies Sir George Stubbs as James Folliat, Amy Folliat's son, whose death had been accepted after a troubled past. Amy helped him assume a new life and marry the wealthy Hattie. The real Hattie was murdered, and her body was concealed beneath the folly; an accomplice then impersonated her while James used her wealth as Sir George. At the fete the false Hattie changed into ordinary tourist clothes and left among the visitors, so her disappearance required no abduction. Etienne de Sousa's visit endangered the scheme because he knew the real Hattie, and Marlene Tucker had picked up enough of the hidden history from her grandfather to demand money. Sir George strangled Marlene in the boathouse, using Mrs Oliver's murder hunt to place her alone and to confuse movements around her. Poirot confronts Amy with the crimes enabled by her protection of her son. The assumed identities and the prosperous life at Nasse House collapse under the solution.

Poirot reveals that Sir George Stubbs is really James Folliat, Amy Folliat's son, believed dead after a disreputable past. Amy helped give him a new identity and arranged his marriage to the wealthy Hattie. The woman seen as Lady Stubbs at Nasse House was an accomplice impersonating the real Hattie, who had been killed so James could control her fortune; the real woman's body was concealed beneath the folly. During the fete, the impostor changed clothes and left among the visitors, making Lady Stubbs appear to vanish. Marlene Tucker had learned enough from her grandfather's observations to blackmail Sir George, so he killed her in the boathouse while the murder hunt provided access and confusion. Etienne de Sousa's arrival threatened the impersonation because he knew his true cousin, which forced the conspirators' timetable. Poirot confronts Amy with the consequences of protecting her son. The false Sir George cannot preserve the identity and estate built on the murders, while Amy is left facing the ruin she tried to prevent.