Norfolk, VA -- The Baltimore Clipper, the Reckoning, leaves port on a 10-day run to Cadiz, Spain, carrying the U.S. Secretary of War on a diplomatic mission. But a sudden squall send them off course into an area where the winds seldom blow and sailing ships become trapped: the Sargasso Sea. The crew soon discovers that the hold is full of illegal weapons, their purpose shrouded in mystery. And that something huge, ancient, and sinister lurks beneath the weeds holding their ship in place.