The Great Fire has ravaged London, wreaking destruction and devastation wherever its flames spread. Now, guided by the incorruptible Fire Court, the city is slowly rebuilding, but times are volatile and danger is only ever a heartbeat away. James Marwood, son of a traitor, is thrust into this treacherous environment when his ailing father claims to have stumbled upon a murdered woman in the very place where the Fire Court sits. Then his father is run down and killed. Accident? Or another murder.? Determined to uncover the truth, Marwood turns to the one person he can trust - Cat Lovett, the daughter of a despised regicide. Marwood has helped her in the past. Now it's her turn to help him. But then comes a third death. and Marwood and Cat are forced to confront a vicious and increasingly desperate killer whose actions threaten the future of the city itself.