February 1574. Winter holds London in its icy grasp, but the city is also caught in a fervour of paranoia, superstition and rumour. Mob violence is commonplace. A whispered word is all it takes to condemn a woman to burn as a witch.

Following his success in foiling the 'Incendium' plot against the queen, Dr Christopher Radcliff's standing within court is high. However, he has no time to reap any rewards. Counterfeit coins are circulating on London's streets, bearing the likeness of his master, Robert Dudley, Earl of Leicester. This in itself is a treasonous offence, but slogans have also begun to appear. Daubed on walls and doorways, they suggest that someone close to the queen harbours treacherous intent - none other than Leicester himself . . .

So Radcliff and his team of informants and amateur spies are sent out into the city's markets, drinking dens and brothels to track down who might be behind such outrageous and subversive acts. The investigation will lead them down a murderous path to face an elusive foe with an extraordinary agenda. And time is running out: for when rumour and fear catch fire, then surely violent insurrection and bloody chaos will follow.