A nurse is called in to assist Mrs. Leidner, a lady with a case of nerves. Mrs. Leidner imagines that she sees a face at the window, tapping on the walls, and seems to be afraid of strangers. When a murder seems to confirm Mrs. Leidner's fears, Poirot is called in to investigate. It is difficult to find definite proof, but Poirot trusts his little gray cells to unravel the mystery of the personalities involved. If he can only understand the personality of each person who was present at the time of the murder, their little jealousies and rivalries will point to the killer. Poirot relies on the eye-witness testimony of the nurse as the only unbiased person there.

I love that this mystery is told from the perspective of the nurse. Her impression of Poirot is hilarious and splendid. She relates to him as if he were the surgeon on a case, and she is the nurse there to assist him. I really enjoyed her narrative voice and the way that she observes all the other characters. She is also a little bit of an unreliable witness, because she makes snap judgments about people, assuming that they must be the good guys. While Poirot suspects everyone and so arrives at the truth.

The mystery is particularly good in this one! The plot really keeps you guessing, and there are plenty of red herrings, but it all makes sense in the end. Unfortunately, I had already watched the TV episode of this mystery before reading it, and so I already knew the ending; but that did not diminish my enjoyment of the story. It was still really wonderful to revisit this mystery and see all the little clues laid out in order.

I did feel like there are a few too many characters in this story. The story could have been told without quite so many side characters. At least three of them could have been done away with, since they didn't play any major part in the story. As it is, it takes a while to be able to remember who everyone is. But since the nurse is also being introduced to all the characters for the first time, we get to learn who everyone is through her eyes, and that makes it more memorable.

I really liked the psychological aspect of this story. There aren't many concrete clues, and so Poirot relies on his ability to analyze each person's personality. Are they the kind of person who would do this or that? Was the deceased the kind of person who would write that letter, or was it a forgery? A lot of the focus is on the personality of the deceased person and their influence on everyone else. Poirot goes around asking each person's opinion of the deceased, and he gets a multitude of conflicting answers. Some say they were an angel, some say a fiend, some say a selfish trouble-maker. His little gray cells must work to discover the truth behind all these different impressions.

Agatha Christie's writing style is just so phenomenal, and Poirot is one of my favorite detectives of all time!