I knew the smell of death well enough. But here the sweetness of decay was tainted with something else, something new and different. It was a curious, moist smell; a smell that spoke of the ooze and slap of water, of gurgling wet spaces and the sticky, yielding mud of low-tide. Summoned to the riverside by the desperate, scribbled note of an old friend, Jem Flockhart and Will Quartermain find themselves on board the seamen's floating hospital, an old hulk known only as The Blood, where prejudice, ambition and murder seethe beneath a veneer of medical respectability. On shore, a young woman, a known prostitute, is found drowned in a derelict boatyard. A man leaps to his death into the Thames, driven mad by poison and fear. The events are linked - but how?