 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 that her own son would inherit the title and estate.As stated at the beginning of the story, Carstairs later died, and his notes containing the details of the case were subsequently found.