This novel tells the story of Kimball O' Hara (Kim), who is the orphaned son of a soldier in the Irish regiment stationed in India during the British Raj. It describes Kim's life and adventures from street vagabond, to his adoption by his father's regiment and recruitment into espionage.

Harvey Cheyne, the pampered fifteen-year-old son of an American millionaire, is sailing to Europe when he falls overboard. Saved from drowning by a New England fishing schooner, he finds his rough new companions unimpressed by his wealth and shocked by his ignorance. He will have to prove his worth in the only way the captain and crew will accept: through the slow and arduous mastery of skills upon which their common survival depends.