The last of Margaret Rutherford's "Miss Marple" films, Murder Ahoy is the only one of the series not based on an Agatha Christie original. The setting this time is a boat that has been purchased by a trusteeship to serve as a home for wayward kids. One of the trustees, Cecil Ffolly-Hardwicke (Henry Longhurst), dies while attending a meeting held aboard the boat. The police write the death off as "natural causes," but another trustee, our Miss Marple (Rutherford), suspects otherwise. Doing a little sleuthing on her own, she discovers that outwardly respectable Lionel Jeffries is using the boat as a "training school" for aspiring criminals, a la Fagin. This would seem to explain why Hardwicke was murdered, but Jeffries is much too obvious a suspect--as Miss Marple discovers nearly too late. Margaret Rutherford's husband Stringer Davis is back again as Miss Marple's platonic middle-aged friend Mr.