Based on the search results, "What Moves the Dead" is a book by T. Kingfisher, a retelling of Edgar Allan Poes classic "The Fall of the House of Usher". The book tells the story of Alex Easton, a non-binary retired soldier, who receives a letter from their childhood friend Madeline Usher, who thinks she may be dying. Alex rushes to the Usher castle to help, but finds a half-caved-in manor on the edge of a sickly lake called a tarn. The book is described as a gripping and atmospheric horror story, with elements of fungi and mushrooms playing a big part in the story.
Therefore, the answer to the question "what moves the dead" cannot be found in the search results, as it is not related to the book "What Moves the Dead" by T. Kingfisher.
