In the sapping summer heat of 1665 there is little celebration in plague-ridden London of the naval victory at the Battle of Lowestoft. At Chelsea, with fine mansions leased to minor members of the Court, there are more immediate concerns: the government has commandeered the theological college to house Dutch prisoners of war. Moreover, a vicious strangler is stalking the neighbourhood. Thomas Chaloner is sent to investigate the murder of the first victim, an inmate of a private sanatorium known as Gorges. He realises, though, that Gorges has stronger links to the prison than just proximity, and that the influx of strangers offers plenty of camouflage for a killer.