The Wolfman is killing women in London, brutalizing them after death, and then biting their abdomens. Rebus may not be an expert on serial killers, but he's a good detective and as an outsider, someone who can look at the case from a fresh angle. That angle includes listening to a psychologist who's researching serial killers, a flash of insight while wandering through an open air market, and another one while musing on the different English dialects. That turns out to be the key to the case, and leads to a car chase through central London with a judge along for the ride.
Rankin initially set out to write straight novels rather than mysteries (although if your first book involves a series of murders and your second high level corruption, you need to be fairly dense to not realize that you're a mystery writer), and while he seems to have come to terms with his genre status in Tooth and Nail, he does include a domestic subplot. Rebus's wife had moved to London with their daughter a few years earlier, and Sammy is now 16 and seeing a rising criminal. Rankin handles this better than most of the subplot-heavy mysteries I've read since starting this blog - it doesn't take up too much of the book or feel like an afterthought, and the links between the two are believable coincidences. Still, it's the least satisfying part of the book, mainly because Rhona is so faintly drawn and Sammy seems less fully fleshed than she did five years earlier in Knots and Crosses. But maybe that's the point - Rebus is a stranger in London and what drives that home more than finding out that he's a stranger to his daughter?