Wasps' Nest is a short story by Agatha Christie which was first published in the Daily Mail on 20 November 1928 in the U.K. and Detective Story Magazine on 9 March 1929. It was later gathered as part of the anthology Double Sin and Other Stories published in 1961 by Dodd, Mead and Company in the U.S. In the U.K. the story was not anthologised until it was included in Poirot's Early Cases in 1974.
Poirot visits a friend, John Harrison, and tells him he is on a mission to solve a murder that has not yet been committed.
(may contain spoilers - click on expand to read)
Sitting on the garden terrace of his large house on a summer evening, John Harrison is delighted to receive an unexpected visit from Hercule Poirot. The detective tells him that he is in the locality to investigate a murder but amazes Harrison by admitting that the murder has not yet been committed but that it is better to prevent one happening first. He then cryptically turns the conversation round to a wasp's nest on a tree that he sees nearby and Poirot and Harrison discuss the destruction of it. A friend of Harrison, Claude Langton, is going to handle the task for him using petrol injected by a garden syringe but Poirot tells him that earlier that day he saw the poison book in a local chemist's and an earlier entry made by Langton for the purchase of cyanide, despite Langton having told Harrison that such substances shouldn't ever be available for pest control. Poirot asks a quiet question: "Do you like Langton?" and they talk of Harrison's engagement to a girl called Molly Deane who was previously engaged to Langton. As they discuss Langton's disposition towards Harrison, Poirot's meaning becomes quite clear to the other man – he is being warned. Poirot asks when Langton is returning and is told nine o'clock that evening. Poirot tells him that he will return at that time, wondering as he goes if he should have waited behind.
Poirot returns just before the appointed time to find Langton leaving, the nest still intact. Harrison seems to be fine and Poirot hopes that he is not feeling any ill-effects of having digested the harmless washing soda that he consumed. Harrison is surprised. Poirot explains. He expected Harrison had been keeping some cyanide in his right pocket. When Poirot visited him earlier on, he had picked the pocket and switched the cyanide for washing soda.
Earlier on, Poirot had met Langton at a chemists and saw that Langton had bought some cyanide. Langton had told him that Harrison had insisted on the use of cyanide over petrol to kill the wasps. This struck Poirot is strange because at a recent dinner, Harrison had condemned the sale of cyanide as an insecticide.
Poirot had also witnessed the signs of Langton's romance with Molly Deane being rekindled and had seen Harrison leaving a Harley Street consultant having obviously been given bad news. Harrison confirms that he has two months to live. Having seen signs of Harrison's hatred for Langton, Poirot surmised that Harrison was planning to commit suicide and make it appear that Langton had killed him, ensuring that his rival would be hanged for murder. Poirot's earlier conversation included several traps, including the time of Langton's appointment. Poirot already knew Langton was due to return at eight-thirty but Harrison said it was nine, by which time he hoped to have committed the deed. Having realise and repented of what he would have done, Harrison expresses his gratitude for Poirot having visited and spoiled his plans.
Film, TV, or theatrical versions
BBC TV Play
Agatha Christie herself adapted the story as a television play, under the title The Wasp's Nest, broadcast on the BBC Television Service on 18 June 1937. It was likely the earliest television dramatisation of an Agatha Christie story and the only one adapted by the novelist herself. It was only broadcast in the London area as this was the only zone able to receive transmissions at that time.
Agatha Christie's Poirot
A television film with David Suchet as Poirot was produced as episode 5 of Series 3 of the ITV series Agatha Christie's Poirot, first broadcast on 27 January 1991. The basic premise of the story was unchanged but the original story comprised mainly a bare-bones narrative by Poirot and included him recalling events from some time ago. This would have been almost impossible to dramatise as is. In the film, events are presented sequentially with many added plot elements and scenes.