Hallowe'en Party by Agatha Christie Pocket Books, 1986 (originally published 1969); 255 pages
Thirteen-year-old Joyce Reynolds is found drowned in the apple-bobbing tub at a Halloween party after she claims to have witnessed a murder when she was younger. Because Joyce was known to exaggerate events to make herself seem more important and because mystery novelist Ariadne Oliver attended the party and Joyce wanted to impress the famous writer. While most people assume that Joyce was killed by a sociopathic tramp, Ariadne believes that she might have been murdered because of her claim to have witnessed a murder. Ariadne takes her theory to Hercule Poirot, who takes the case.
Hallowe'en Party is one of Christie's later novels, which I don't consider to be nearly as good as her work from the 1920s, '30s, and '40s. The plot meanders through so many irrelevant details, seemingly not in an effort to create red herrings, but for no good reason whatsoever. Christie also seems to use the novel as a vehicle for discussion of the British justice system in the mid-twentieth century, as many of the characters either lament the lack of justice since hanging was done away with or try to explain all criminals as being merely misunderstood and coming from a bad childhood.
In terms of the conclusion, parts of the "big reveal" for which Poirot is so famous don't make any sense with the rest of the story--there is not one bit of evidence concerning the actions of two characters in relation to a subplot, yet somehow Poirot guessed correctly.
On the whole, Hallowe'en Party is unsatisfying as a mystery, and doesn't even have enough of Christie's creative spark to carry the illogical plot or the annoying M. Poirot. The only highlight is Christie's excellent descriptive passages of characters and settings.