On the broad northern pavement of Leicester Square, three young men meet after years of separation. At first it seems that their circumstances are now very different, for while Challoner is still as well dressed as ever, Paul Somerset, a barrister, is hard pressed to make a living, while Desborough, the youngest, is idle, 'waiting for something to turn up'. But it turns out that all are down on their luck. 'What', they ask, 'can a young fellow of reasonable education do with a hundred pounds?' Concluding that the life of a detective is the only profession for a gentleman, the three disperse to pursue their investigations.
The story moves from the pavements of London to frontier America, with its Mormon caravans and dark deeds at Salt Lake City, on to slavery and voodoo on a Caribbean island, and back to London lodging houses and the secret underworld of anarchists and bomb plots.
First published in 1885, this is the only book that Stevenson wrote in collaboration with his wife, Fanny, and the plot recalls the Fenian problems which were current in London during the period. The book is dramatic, funny, exciting and always supremely readable.