<p>Mustachioed sleuth Hercule Poirot receives a letter challenging him to solve a murder that has yet to be committed. The clues? A date and a location, and the signature A.B.C. Soon Alice Ascher is killed in Andover, an open A.B.C. railway guide near her body. Next it's Betty Barnard, strangled in Bexhill. Can Poirot find the serial killer before he — or she — goes through the entire alphabet?</p>