"Third Girl" was a strange and dispiriting journey for me.
At the start of the book, I was pleasantly surprised at the contemporary (1960's) feel of the novel. There was much more humour in it than I'd expected but there was also more violence and a deeper sense of threat than in other Poirot novels I've read.
I loved the opening where Norma, (a young woman who is constantly referred to as a girl) interrupts Poirot's breakfast, insisting that she needs to talk to him about a murder and then leaves without giving him any details, telling him that, having met him face to face, she can see he's too old to be able to help her. This was a splendid inversion of the Philip Marlowe type of opening scene where the femme fatale uses her allure to get the hard-bitten gumshoe's help. It was also perfectly calculated to ensure Poirot's enthusiastic engagement.
I also greatly enjoyed seeing the inimitable and indomitable Adriadne Oliver playing detective. She was a complete hoot, a wonderful example of misplaced confidence arising from a broad imagination married to narrow experience.
All the best scenes in the book had Adriadne in them. Her presence brought the dialogue alive. She's so much easier to like than Poirot and her pen sketches of the young people in the allegedly swinging London of 1966 were refreshing: the young man with the pretty hair and the gaudy clothes that she calls "The Peacock", the artist working in oils that she refers to simply as "The Dirty One" and the young model who she describes as throwing herself into Burne-Jones poses with admirable flexibility. There's no malice here, just a naive observation by someone who has no qualms about not being in tune with the times.
I had no idea what was going on or how the plot strands would come together but I was enjoying the journey.
By the time I was midway through the book, my disappointment had begun. I continued to enjoy Poirot's dry wit, Ariadne's blustering slapstick and the carefully nuanced descriptions of people's characters but those things began to be outweighed by the large chunks of clumsy plot exposition that even Hugh Fraser's narration couldn't make interesting. I was also starting to be irritated by the deeply conservative attitudes towards gender and mental health. I felt as though I was dipping blindly into a box of Bertie Bott's Every Flavour Beans: I might get something that made me smile or something that made me want to wash the taste away.
The last third of the book was a chore. There were repeated attempts at sharing Poirot's thought processes, which was irritating as they were mostly plot recaps, lacked any analysis and reached no conclusions. The psychiatrist who is instrumental in resolving the plot managed, despite having all the credibility of a cardboard cutout, to be deeply offensive both as a person and as a mental health practitioner.
The plot, when it finally emerged from the detritus-ridden undergrowth we had all wriggled through, was moderately clever but was spoiled for me by one of the early Mission Impossible TV Series moments when a mask is pulled off a main character and he or she is instantly revealed to be someone else. This was limp at best.
What disappointed me even more than the cheat in the big reveal was the way in which Norma was treated. The outcome stretched my willingness to suspend disbelief and angered me because it so demeaned the woman who, as the novel progressed moved from main character to semi-plausible plot-device, to the punchline of a French farce.
If this has been my first Agatha Christie, it might well have been my last. As it is, I'm going to read "The Murder Of Roger Ackroyd" in the hope of demonstrating to myself that Poirot stories once had substance.