Set on Lake Champlain, the narrative follows Dory Dornwood and other youths as Captain Gildrock establishes a Beech-Hill Industrial School where boys learn practical trades. Adventures on the water—collisions, rescues, and skirmishes—alternate with workshop scenes at the carpenter's bench and machine shop, classroom debates about vocational education, and lessons in navigation and seamanship. Portraits of fellow students and local families provide interpersonal episodes and small conflicts, while descriptions of tools, benchwork, and organized shipboard life aim to spark interest in mechanics and practical learning.