I wasn't planning on using this for the 12 tasks, but it is set in the UK! One more down...
Helen and Geoff plan for a nice weekend at a cottage in the Forest of Dean. During their stay, they find an idyllic setting with a small cottage foundation that they villagers call ‘The Glade.’ Helen and Geoff are pulled towards the Glade and want to build a home there. They are warned off from the area by everyone in town, but Helen and Geoff proceed anyway, especially when Helen learns of her terminal diagnosis. Their country cottage was supposed to be a place where Helen went to die; instead she is one of the few left alive. Everyone told her that the Glade wanted something from her, but Helen could never imagine what exactly the cost would be.
This is a fast paced mix of murder mystery, horror, and thriller. From the very beginning we know that Helen has somehow killed Geoff and the chapters go back and forth between the events leading up to the murder and Helen being arrested. This made me extremely interested in what exactly had happened to get to this point. At first, it seemed to me that the mystery of the Glade was pretty clear cut and I was having trouble seeing how its powers were a bad thing. However, the Glade moves quickly and little by little things begin to turn for the worse. The writing builds suspense masterfully as inklings of something wrong comes to you from every direction up until the very end. By about 60% through, I really had no idea where this was taking me and just went for the ride. My only complaint would be the overuse of the word "whilst." Seriously, everything was whilst they were doing something or other. With strong scenes of violence, gore and overall weirdness, this may not be for everyone, but it worked for me.