When Marie Morisot, a notorious money-lender is found murdered on a plane, practically every other person on board is tagged with a motive that makes him or her suspicion till the final dramatic moment....could it be the unknown daughter posing as someone else? the embezzling Englishman? perhaps the archaeologist who seems to be forging antiquities? Luckily, or unluckily for the murderer, Hercule Poirot was also on that flight, and he doesn't take kindly to murder happening under his very nose!
In most of her novels, Christie manages to start the whole investigation off with some sort of preconceived idea of the murder......that's what you have to watch out for. The start of an investigation is the most crucial in any Christie novel because the statements and ideas of the murder by the detective are almost always initially wrong! For example (spoiler alert) in Death in the Clouds, the idea is that the murder was committed by someone passing by the victim (with the possibility of a blow-pipe floating around in the background confusing the whole issue) and therefore, automatically the characters are divided into possibilities and non-possibilities: people who passed the victim and others who definitely did not. It's the 'did nots' that you have to look out for! There is always some sort of illusion at work which keeps the detective, and us, away from the reality of the murder. (Talk about suspecting the least likely suspect!)
So, reading back, I see I've been rambling, but I can't make my meaning any clearer. Perhaps, reading more Christie will help me to put my finger on it! All in all, not one of my favorites.