Once a well-known prize-fighter with a terrifying right arm (christened ‘the hammer of heaven’), Daniel O’Thunder has seen the light, and now the protection of the poor and weak is his life’s work. He runs an establishment for those in need of food, shelter and counsel – a place where virtue and vice rub shoulders uneasily. Vagrants, rogues and streetwalkers are attracted to his charismatic presence, including Nell, the foul-mouthed, golden-hearted prostitute, and Jack, a spectacularly failed cleric with dark secrets. And as they are drawn to O’Thunder, their own stories begin to unfold.

But for Daniel, this work isn’t good enough. For an ancient evil is stalking London’s streets, preying on the vulnerable souls it finds there: an evil that takes different forms and hides behind many faces; a menace that murders and tortures, and threatens everything he loves most. It is an evil that must be fought in the only way Daniel knows how – with his fists.