After discovering a communication capsule from the lost submarine "Starbuck", Dirk Pitt is seconded from NUMA to the 101st Salvage Fleet and ordered to help get to the bottom of the mysterious disappearance of the top-secret submarine. Pitt discovers that the submarine went missing in an area of the Pacific Ocean north of the Hawaiian island of Oahu nicknamed the "Pacific Vortex". Similar in its mysterious reputation to the Bermuda Triangle, the Navy has documented 37 cases of ships vanishing without a trace with all hands in this area of the Pacific since 1956.