A story of London of the middle 1800's -- a London of contrasts even greater than today, of mordid horrible slums, through whose vices rich men made fortunes. A story of dissolute wretches, of men-and women- on the make, of naive leaders of organisations of betterment taken in by their underlings who have no care for their sources of illegal profit, of idealists done by the very people who should trust them, of prostitutes, panderers and their associates. Chiefly, it is the story of Lottie Heape, rescued from her captors by two youths, and the steps by which she was to become a notorious mistress of a man who was murdered. It is the story too of those youths,- Paul Gladwin, whose steps were dogged by ill luck, and Matt, whose journalistic career succeeded in exposing some of the very evils with which the tale deals. A crowded canvas, with multiplicity of plot and subplot, but the whole conveying a vigorous picture of a sordid and murky undercurrent of a great city's story. Somehow, as one reads, it is the city itself that dominates plot and characters. Sadleir can write- but it is not pleasant reading.