This is what happens when you set your Kindle to "wireless on" and you go on a road trip. Sigh. (If your Kindle has a leaky wireless connection, you will run out of battery by the time you get to your destination. If you are stupid enough not to bring your plug with you just in case or even a real paper book, for heaven's sake, you are hosed.)
The cottage had many mothbally, ancient choices. I have read so many Christie novels in the past that their plots all run together in my head, and it was hard to remember even which were Poirot and which were Marple. This one is neither, so that's a bit of fresh air. Unfortunately, the structure remains exactly the same as every other Christie novel so you know exactly what you'll be getting and when. (Pretty much the definition of a perfect beach read, actually.)
In addition, in this tome you get your usual "fear of foreigners," a thread that never leaves Christie's works and strongly hints at the mindset of the upper class and England in general before, during and after the war years. And double bonus in this one: a diatribe against adopted children. Christie may have been an excellent judge of character and understood the psychology of individuals and groups, but her thoughts are definitely dated for this day and age. I can't imagine how I'd feel if I had been adopted and read this book. Heavens.
In all, a lesser work for sure. If you are desiring some Christie, re-read "Sleeping Murder" or "Murder on the Orient Express." Those are far more satisfying.