Third Girl was first published in 1966. In it Poirot is probably meant to be approaching eighty, although if he had aged with the books he would have been well over a hundred! Anyway, the young lady who comes to see him about ‘a murder she might have committed‘ runs out of his room after blurting out:

‘You’re too old. Nobody told me you were so old. I really don’t want to be rude but – there it is. You’re too old. I’m really very sorry.’ (page 13)

Poirot is bored. He had finished his Magnum Opus, an analysis of detective fiction writers, in which he had spoken scathingly of Edgar Allen Poe, and had complained of the lack of method or order in the romantic outpourings of Wilkie Collins. He had no idea what to do next, so, his interest is aroused by the young lady’s announcement and he sets out to discover what murder she ‘might have committed.’ It turns out that Mrs Ariadne Oliver had told the girl about him when talking with friends about detectives and together they discover that she is Norma Restarick, the ‘third girl’, sharing a flat with two other girls.

Norma thinks she might be crazy, but won’t see a doctor. She doesn’t always remember what she has done. She hates her stepmother and thinks she might have poisoned her. Poirot is intrigued but when a suspicion of espionage surfaces it is all too much for him:

Poirot gave an exasperated sigh.

‘Enfin,’ he said, ‘it is too much! There is far too much. Now we have espionage and counter espionage. All I am seeking is one perfectly simple murder. I begin to suspect that that murder only occurred in a drug addict’s brain! (page 211)

But as Poirot reminds himself it is his ‘metier’ to deal with murder, to clear up murder, to prevent murder and eventually with a casual phrase spoken by Mrs Oliver it all becomes clear to him.

The plot is complex, which is rather puzzling,  but for me Third Girl is also interesting because of its commentary on the 1960s culture seen through the eyes of the older characters – the disparaging remarks about the youth of the day – beatniks, long hair, clothes that were of doubtful cleanliness, and skimpy skirts, and the Van Dyke type clothes some of the young men wore, the drink and drugs and wild parties. Mrs Oliver has her usual gripe about people saying things to her about her books and how they longed to meet her, making her feel ‘hot, bothered and rather silly‘ and how much they love the ‘awful detective Sven Hjerson‘ she had created and now hates.

Maybe it’s not one of Agatha Christie’s best books but I think it’s very entertaining.