A lively tale follows Chap Webster and his friends Philip Berkeley and Phineas Poole as they set off on a tug-boat excursion that expands into a string of river and coastal adventures. Episodes include sea voyages, rescues, encounters with wildlife and alligators, expeditions into unsettled shorelands, leadership contests with rival parties, plots and a climactic race, and encounters with local gentry. Told in episodic chapters, the narrative emphasizes improvisation, youthful daring, practical resourcefulness, and shifting alliances as the boys face physical dangers and social tests before returning to home life.