Rivers of London: Detective Stories #4 (Titan, 2017)

Undergoing his detective exams, PC Peter Grant has been looking back on some of his previous cases. The final one takes him back to one of his first — one that has nothing to do with his other profession: trainee wizard in the Met's Special Assessment Unit. However, it is a time of remembrance past with his old partner, Lesley May — the same partner left mutilated by magic and who has now gone rogue, vanishing into London's mystical underworld. Self-contained magical crimes, as recounted by Detective Peter Grant to his superiors, as he takes the Detective exam. If you've ever wanted to try the mysterious world of Rivers of London, this is the perfect opportunity to get on board! An all-new series of Rivers of London short stories by Ben Aaronovitch and Andrew Cartmel. Set between "The Hanging Tree" and "Black Mould".