Book 3 in the Rivers of London series, from Sunday Times Number One bestselling author Ben Aaronovitch.

Peter Grant is learning magic fast. And it's just as well - he's already had run-ins with the deadly supernatural children of the Thames and a terrifying killer in Soho. Progression in the Police Force is less easy. Especially when you work in a department of two. A department that doesn't even officially exist. A department that if you did describe it to most people would get you laughed at. And then there's his love life. The last person he fell for ended up seriously dead. It wasn't his fault, but still.

Now something horrible is happening in the labyrinth of tunnels that make up the tube system that honeycombs the ancient foundations of London. And delays on the Northern line is the very least of it. Time to call in the Met's Economic and Specialist Crime Unit 9, aka 'The Folly'. Time to call in PC Peter Grant, Britain's Last Wizard.

Praise for the Rivers of London novels:

'Ben Aaronovitch has created a wonderful world full of mystery, magic and fantastic characters. I love being there more than the real London'

NICK FROST

'As brilliant and funny as ever'

THE SUN

'Charming, witty, exciting'

THE INDEPENDENT

'An incredibly fast-moving magical joyride for grown-ups'

THE TIMES

Discover why this incredible series has sold over two million copies around the world. If you're a fan of Terry Pratchett or Douglas Adams - don't panic - you will love Ben Aaronovitch's imaginative, irreverent and all-round irresistible novels.