Soho, 1935. Sergeant Leon Geats' patch.

A snarling, skull-cracking misanthrope, Geats marshals the grimy rabble according to his own elastic moral code.

The narrow alleys are brimming with jazz bars, bookies, blackshirts, ponces and tarts so when a body is found above the Windmill Club, detectives are content to dismiss the case as just another young woman who topped herself early. But Geats - a good man prepared to be a bad one if it keeps the worst of them at bay - knows the dark seams of the city.

Working with his former partner, mercenary Flying Squad sergeant Mark Cassar, Geats obsessively dedicates himself to finding a warped killer - a decision that will reverberate for a lifetime and transform both men in ways they could never expect.