The story of Gilliatt, an illiterate fisherman from Guernsey (Channel Islands), a social outcast in love with Deruchette, the neice of a local shipowner, Mess Lethierry. When Lethierry's ship is wrecked on the Roches Douvres, a perilous reef, Deruchette promises to marry whomever can salvage the ship's steam engine. Gilliatt eagerly volunteers, and the story follows both his physical trials and tribulations (which include contending with sea storms and monstrous predators, including an octous), as well as the undeserved opprobrium of his neighbors. Intended to be part of a triptych with "Les Misérables" and "The Hunchback of Notre-Dame", the book laments the living conditions of impoverished workers, while celebrating their ingenuity and discipline.