Twelve-year-old Samuel Skiff Beaman is a boy with incredible determination. Since the death of his mother, his father has sunk into depression, and now Skiff´s pride and joy, their boat the Mary Rose has sunk too. If only he can raise and fix Rose, Skiff is sure he´ll be able to get the family business, and his dad, back on track. But to fix the boat he needs $5000. Determined to raise the money himself, Skiff decides to go out on the open ocean all alone, on a dangerous mission to harpoon a prize giant tuna.