Hercule Poirot has just completed his analysis of great writers of detective fiction when he is interrupted by Miss Restarick, an unimpressive lass of twenty or so with long straggly hair. The young girl starts by explaining that she might have killed someone, but before Poirot can ask more information, she says she's changed her mind and must leave. Before she closes the door, she adds "You are too old. Nobody told me you were so old... I'm really very sorry." Poirot is intrigued by the girl, and enlists Mrs. Oliver's help in investigating Miss Restarick. The detective duo soon discovers that not only is the girl nowhere to be found, but that no one seems to care that she is missing.
In his thirtieth appearance in a novel, Hercule Poirot is claimed to be too old. But that is surely not what the reader will think of the author's wit and cleverness. At the age of seventy-five Agatha Christie still succeeds in composing a quite entertaining mystery. Admittedly The Third Girl is not one of her masterpieces, but it still has the basic ingredients of a good detective story. The things that have changed more dramatically, in comparison to the novels she wrote in the 30's, are the flamboyant characters that make up the story. It is clear that Agatha Christie does not totally agree with the way teenagers are beginning to behave in the sixties. All they seem interested in is "sniffing snow", "swallowing LSD" and "using hemp". Surely, this is an exaggeration in which Agatha Christie reveals slowly losing touch with modern age.
Nevertheless Poirot is as absurd and as able as ever, which pulls this story out of the pool of mediocrity. And be warned: the book starts of with a vital clue, so try to avoid reading the denouement while blaming yourself: "I should have known it!"