Whispers Underground, by Ben Aaronovitch

The London Underground is the setting for this third book in the Rivers of London series. Constable Peter Grant’s colleague Lesley May has joined him at The Folly as an apprentice wizard. She is still recovering from the horrific facial injuries inflicted by magic in the first book, but is gradually discarding her mask. In this tale the murder of a young American student leads to discovery of a secret underground village of a previously unknown species of magical humans. Peter’s young cousin Abigail makes another appearance, expanding the team of magic learners. All hands are likely to be needed as the so-far fruitless search for the Faceless man and his evil associates ramps up. A lesson in the history and geography of London always comes with these books and this mostly adds to their entertainment.