London: The Crime Club / Collins, (1970) dj. Hardcover first edition - Ninth mystery featuring Scotland Yard Chief Superintendent Henry Tibbett and his wife Emmy, a book in which Moyes takes on the classic country house murder. In this case, Tibbett and Emmy are at the house as guests for Crystal Balaclava's 70th birthday, and also to make sure that Crystal is safe. When she is apparently poisoned in front of everyone, and the autopsy comes back with "natural" causes, Tibbett is determined to solve the mystery of a poison that left no trace. 286 pp. ISBN: 0-002318881.