Who Killed the Earl of Moran?

Mrs. Mary Alder, in discharging her last duty to her mistress, the Dowager Countess of Moran, goes to deliver a list of the aging countess's engagements for the following day to her son, the earl, in his study, only to discover that the earl has been bludgeoned to death. When Mary is accused of the crime, her son, Julian, rushes to his employer, Curtis, of the Curtis Inquiry Agency, for help, and Curtis promptly enlists the aid of Barnaby and Penelope Adair and Scotland Yard's Inspector Sto...