Davy joins the crew of a ketch trading between Barnstaple and Porthcawl. Whilst in Devon, he encounters several characters who hold the key to solving the mystery of the maid of Sker. These include Sir Philip Bampfylde who spends most of his time looking for his two grandchildren who have mysteriously disappeared; Parson Chowne, a parson of demoniac wickedness and craft who works his will for many years in the north of Devon, defying God, man, and the law; and Captain Drake Bamfylde who is under suspicion of having made away with the children of his elder brother, and heirs to the family property. Old Davy gradually unravels the mystery and sets matters right, although many distractions delay him including an extended period at sea in which Blackmore gives a graphic account of the Battle of the Nile.