Ben Aaronovitch & Andrew Cartmel 
Rivers of London [PDF ebook] 
The Fey And The Furious #4

Trouble is never far from Peter Grant, even when he’s off-duty. After suspiciously a suspiciously supernatural cargo washed up on the Netherlands’ shores in the back of a boy racer’s car, Peter infiltrated illegal street races organised by criminal mastermind Emmanuel Cross. His investigation swiftly took a wrong turn as he once again found himself speeding into Fairy Land.Although Peter has uncovered the mysterious cargo’s source — with Cross’s cronies slaughtering unicorns for their horns — he is trapped in this magical realm. To make matters worse, the Fairy Queen has found him and is ready to resolve their unfinished business…