Since we first met Mr. Rafiel of Nemesis in A Carribean Mystery, I listed to that next. This is the one where an old bore asks Miss Marple if she wants to see a photograph of a murderer, stops before showing it her with a startled look on his face, and then ends dead. I don’t recommend experiencing these out of order; Miss Marple doesn’t ally with Mr. Rafiel until late in the book, and Nemesis has oblique but real spoilers for this story.
On its own, though, I’d be a bit dubious about this, as the big revelation that makes the mystery come together doesn’t seem physically plausible to me. Other than Mr. Rafiel, there isn’t too much memorable about this. (I do note that a sort of rough justice occurs with regard to one of the red herrings, which goes unremarked upon by the characters in the adaptation.)