I love Mo Hayder. She writes books that are genuinely quite horrific and always very gripping. The Treatment is no exception. Police find a husband and wife tied up and severely dehydrated in their home. Their nine-year-old son is missing. A desperate hunt ensues, and eventually the child is uncovered, but along the way Jack Caffery, who is leading the investigation, begins to wonder whether there is a link between this and an old case that was dismissed many years ago. The clock is ticking as another family comes under the torturer's scrutiny, but what is actually going on? All the clues seem to point towards the fathers setting the whole thing up, but does this mean they're operating a network of wife- and child-torturers? Caffery works flat-out to bring the case to its dramatic conclusion.