A mutilated body in Crawley. Another killer on the loose. The prime suspect is one Robert Weil - an associate of the twisted magician known as the Faceless Man? Or just a common garden serial killer?
Before PC Peter Grant can get his head round the case, a town planner going under a tube train and a stolen grimoire are adding to his case-load.
So far so London.
But then Peter gets word of something very odd happening in Elephant and Castle, on an housing estate designed by a nutter, built by charlatans and inhabited by the truly desperate.
Is there a connection?
And if there is, why oh why did it have to be South of the River?
Full of warmth, sly humour and a rich cornucopia of things you never knew about London, Aaronovitch's series has swiftly added Grant's magical London to Rebus' Edinburgh and Morse's Oxford as a destination of choice for those who love their crime with something a little extra.