Because it is a movie, Marple visits the home of wealthy and frail Enderby (Finlay Currie) at the moment of his death, caused by, of all things, a cat. Marple's exquisite timing continues: she snoops on the reading of the Enderby will just at the moment when the value of the estate is disclosed and timid Miss Milchrest (Flora Robson) suggests that the hapless Enderby was murdered.
Naturally, all of the Enderby family are suspect. These include the aforementioned Robson, in addition to fox hunter Hector (Robert Morley), brunette hottie Rosamund (Katya Douglas), her spendthrift husband Michael (James Villiers), and the ever unpleasant Crossfield (Robert Urquhart).
Hector is the comic relief character of the story, which borders on comedy in any event. Hector is delighted to learn that Marple is a horse rider, and seems bent on courting the sleuthing equestrian. But Hector's servant, Hillman (Duncan Lamont), is a creepy and burly sort who regards Marple as a meddler. Which indeed she is.
How others will see it. Given that the lead is an elderly woman, it is unsurprising that the audience that favor the film most are women over 30. However, the spread is relatively narrow between men and older women. Clearly, men also regard the moderately entertaining comic mystery as well done, albeit unremarkable.
How I felt about it. The presence of Robert Morley and Flora Robson are welcome. Katya Douglas is lovely to admire, and we are actually pleased when Crossfield gets his. Still, the idea of dumpy septuagenarian Marple as an expert side saddle rider seems a bit of a stretch, and whoever killed someone by putting a cat in their house? Marple's proximity to all three murders is beyond coincidence, and should make her the chief suspect.
The movie is a comedy, but in the droll style of English humor. Thus, we are supposed to be charmed when Robert Morley fawns over an old saddle, or when Rutherford "gets down" on the dance floor with obliging Stringer Davis, or when Rutherford shamelessly eavesdrops on private conversations. Or when Morley proposes to the hunchbacked and obese Rutherford! Well, she has the potential for engaging conversation.
These moments are the highpoints of the movie, and the impact of their charm determines how you will regard Murder at the Gallop (based on the novel "After the Funeral," which featured Hercule Poirot). The conveyed charm will have to overcome the frivolous nature of the screenplay, which has Marple using the million dollar painting (in today's money) as a hatpin for Robson's hypodermic.