This is one of my favourite Poirot mysteries. It has a lot of the things that Christie does so well: a surprise ending that sneaks up on you; some spectacularly snooty and humorous characters, in this case the stand-out is the vague and offhand socialite, Lucy Angkatell; and a heart-warming but not too intrusive bit of romance.
The Hollow is the name of the manor house where Lucy and Sir Henry like to entertain, inviting their friends and relations for weekends. This weekend Lucy is in a bit of a dither having invited too many problematic guests - the distant cousin, David, just down from Oxford who has socialist leanings, the excessively charming Dr John Chistow and his mousy wife Gerda who gets flummoxed by the Angkatell's idea of fun.
Unfortunately, Henrietta, another cousin also invited, happens to be John's mistress, while yet another guest is cousin Edward, who has always loved Henrietta. It is just as well Henrietta is so lovely with Gerda and manages to smooth over any awkwardnesses. Then there's Midge, the 'poor cousin' of this cast of relatives who, God forbid, has to work in a dress shop where she is treated like a dogsbody just to earn a living.
Over an evening at the bridge tables all these potential issues are beginning to simmer when in through the French windows - Christie is a whizz at entrances - appears a glamorous actress in evening dress, asking for matches. She's none other than Veronica Cray, an old flame of John Christow's and the only woman he ever truly loved. He escorts her back to her weekend cottage and returns rather later than expected. Oh, dear.
Of course the final guest is Hercule Poirot, invited for lunch the next day, and he arrives just in time to see a tableau that at first he thinks with immense irritation has been assembled just for his benefit - a dying man (John Christow) lying at the edge of the pool, his wife standing looking dazed and holding a pistol, while other members of the party appear from all directions.
The scene is set for a wonderful whodunnit: loads of motives, red herrings and an oversupply of guns. It doesn't have the tension of say The ABC Murders, with more people being bumped off continually though the book. Instead are some comical scenes starring Lucy Angkatell, a supreme snob, though she tries to be kindly, and some insight into the predicament of nicely brought up young ladies with limited means who must therefore marry or work to support themselves.
Henrietta does this most successfully as a sculptor, while Midge has to encourage snooty matrons to buy expensive clothes they don't really need. This is post-war Britain after all and the times they are a-changing.
The men don't necessarily have such a nice time of it either - there's the irony of David being all set to inherit The Hollow, when he would really like to set a torch to it, while Edward has been unmanned by being wealthy. He has never had to make a career for himself so thinks he's no good at anything. John Christow puts them all in the shade - he's a brilliant doctor, charming and charismatic, but oh so tired, and not long into the book, he's oh so dead.
All in all, this is just another murder mystery, with Poirot getting his little grey cells into gear, but it still manages to be a very satisfying read, with plenty of wit and the effect of watching an engaging if slightly old fashioned play. Things crank up towards the end with the possibility of another murder but Poirot steps in just in time to nip it in the bud. Just as it should be.