What a cute short story! I love revisiting Miss Marple. I think I read this in a collection before, but it seemed to be longer in this version which was weird. 

"The Case of the Caretaker" has Miss Marple getting over a nasty flu. She's down and out and being morose. Her friend and doctor, Doctor Haydock, invites her to read a story he is writing and wondering if she can figure out the whodunit. It's based on something real in the doctor's life. 

I always go back to Christie since she can set a scene. We get to get into the heads of several characters via Doctor Haydock's story. Harry Laxton has returned home married after a somewhat scandalous past to St. Mary's Mead. Harry has torn down his old ancestral home and built something new and shiny. He also turfed out the former's caretaker's wife who keeps popping up like the Babadook and harasses his new wife. The doctor comes into play since his niece feels very protective of the Harry and his wife. When Harry's wife is thrown from the horse after the caretaker ambushes her again, Doctor Haydock asks Miss Marple what does she think.

Honestly I was surprised at the ending since I didn't see it coming. I just thought what Christie wanted me to think and of course re-read this since the clues are all there. I thought it was a clever story and loved how Miss Marple puts things together.