After the death of their grandfather, Will and Sara escaped with their nanny in the middle of the night, fleeing the treachery and greed of their grandfather's second wife who will stop at nothing to destroy what stands between her and the massive Trent fortune. Will and Sara's lives are thrown into chaos, enduring the sinking of the Northwind, dealing with sharks, storms and starvation, relying only on their wits and close relationship to stay alive. Alone in the world until they read the letter, given to them by their nanny, from their late grandfather, a letter that will change their lives forever, if they can survive the perils that lay before them.