A Rivers of London novella, from Sunday Times Number One bestselling author Ben Aaronovitch.

There's something going bump on the Metropolitan line and Sergeant Jaget Kumar knows exactly who to call. It's PC Peter Grant's speciality...

Only it's more than going 'bump'. Traumatised travellers have been reporting strange encounters on their morning commute, with strangely dressed people trying to deliver an urgent message. Stranger still, despite calling the police themselves, within a few minutes the commuters have already forgotten the encounter - making the follow up interviews rather difficult.

So with a little help from Abigail and Toby the ghost hunting dog, Peter and Jaget are heading out on a ghost hunting expedition. Because finding the ghost and deciphering their urgent message might just be a matter of life and death.

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 and novellas.