At fourteen the unworldly, idealistic Jack Easy leaves the luxury of his father's estate in England and sails into a world of action and adventure aboard the sloop of war HMS Harpy. At first Jack finds it hard to stomach the discipline of naval life and, with his mischievous sense of humor, is always getting himself into scrapes. But soon he is bravely taming a band of mutineering seamen, outwitting a wily and murderous Sicilian nobleman, and breathing the smell of gunpowder and raw steel as the Harpy chases Spanish ships on the Mediterranean.