It tells the story of Thomas Saunders, a sailor's son and neglected street urchin struggling to survive in Greenwich, London in the early 19th century. ("Poor Jack" was the title given by the waterfront boys, or mudlarks, to their chief.) In a rags-to-riches story, Saunders eventually rises by his own efforts to become a pilot on the Thames, makes his fortune and retires to the life of a wealthy squire.