On a cool June morning, a woman is walking her dog in the idyllic coastal village of Salten along a tidal estuary known as the Reach. Before she can stop him, the dog charges into the water to retrieve what first appears to be a wayward stick, but to her horror, turns out to be something much more sinister... The next morning, three women in and around London—Fatima, Thea, and Isabel—receive the text they had always hoped would NEVER come, from the fourth in their formerly inseparable clique,...