The Roaring 20s. The luxury steamship Benjamin Franklin leaves Genoa and sets out on a transatlantic voyage it has taken many times in the past. Things do not go to plan, however, when the ship is caught in a storm and seriously damaged.

In all the confusion and panic, three passengers are left behind. A criminal, a detective who captured him, and an heiress must face a journey far away from the regular transoceanic routes, into the heart of the treacherous Sargasso Sea - a journey that will change their lives forever.