The Strange Case of Sir Arthur Carmichael is a short story written by Agatha Christie.
Dr Edward Carstairs, a noted psychologist, is called in to investigate the case of Sir Arthur Carmichael, a young man of twenty-three who woke up the previous morning at his estate in Herefordshire with a totally changed personality. Carstairs travels down there with a colleague called Dr Settle who tells him that he feels that the house could be haunted and this phenomenon has connections with the case. The household consists of Sir Arthur, his stepmother, Lady Carmichael, his half-brother of eight years of age and a Miss Phyllis Patterson who Arthur is engaged to be married to. As their horse carriage comes up the drive, they see Miss Patterson walking across the lawn and Carstairs remarks on the cat at her feet which provokes a startled reaction in Settle.
Going into the house they make the acquaintance of Lady Carmichael and Miss Patterson and again Carstairs causes a reaction when he mentions seeing the cat. They then see their patient and observe his strange behaviour – sat hunched without speaking, then stretching and yawning and drinking a cup of milk without using his hands.
After dinner that night, Carstairs hears a cat meowing and this sound is repeated during the night outside his bedroom door but he is unable to find the animal in the house. The next morning he does spy the cat from the bedroom window as it walks across the lawn and straight through a flock of birds who seem oblivious to its presence. He is further puzzled when Lady Carmichael insists that there is no cat in their home. Talking to a footman, Carstairs is informed that there used to be a cat but it was destroyed a week ago and buried in the grounds. There are further appearances of this apparition and they realise that it is targeting Lady Carmichael. Carstairs even dreams of the cat the following night when he follows it into the library and it shows him to a gap in the volumes on the bookshelf. The next morning, Carstairs and Settle find that there is a book missing from the very spot in the room and Carstairs glimpses the truth later on in the day when Sir Arthur jumps off his chair when he spots a mouse and crouches near the wainscoting, waiting for it to appear.
That night, Lady Carmichael is badly attacked in her bed by the ghostly creature and this prompts Carstairs to insist that the body of the dead cat is dug up. It is and he sees that it is the very creature that he has spotted several times and a smell shows that it was killed by prussic acid.
Several days pass as Lady Carmichael starts to recover until one day Sir Arthur falls into the water of the lake. Pulled out to the bank, it is first thought that he is dead but he comes round and he has also recovered his personality but he has no recollection of the intervening days. The sight of him gives Lady Carmichael such a shock that she dies on the spot and the missing book from the library is found – a volume on the subject of the transformation of people into animals. The inference is that lady Carmichael used the book to put Sir Arthur's soul into the cat, then killed it to ensure her own son would inherit the title and estate. As stated at the beginning of the book, Carstairs died later, and his notes containing the details of the case were found.
- Dr Edward Carstairs
- Sir Arthur Carmichael
- Lady Carmichael
- Dr Settle
- Miss Phyllis Patterson