William Avery is a young soldier with few prospects except rotting away in campaigns in India; Jeremiah Blake is a secret political agent gone native, a genius at languages and disguises, disenchanted with the whole ethos of British rule, but who cannot resist the challenge of an unresolved mystery. What starts as a wild goose chase for this unlikely pair --- trying to track down a missing writer who lifts the lid on Calcutta society --- becomes much more sinister as Blake and Avery get sucked into the mysterious Thuggee cult and its even more ominous suppression.