London, May 1665. On a dark road outside London, a simple robbery goes horribly wrong – when the gentlemanly highwayman, William Coke, discovers that his intended victims have been brutally slaughtered. Suspected of the murders, Coke is forced into an uneasy alliance with the man who pursues him – the relentless thief-taker, Pitman. Together they seek the killer – and uncover a conspiracy that reaches from the glittering, debauched court of King Charles to the worst slum in the city, St Giles in the Fields. But there's another murderer moving through the slums, the taverns and palaces, slipping under the doorways of the rich. A mass murderer. Plague.