This series explores the fascinating dark side of the Ocean. Four episodes present the complete and definitive story of the world's oceans through the prism of its five deadly forces tides and currents, pressure, waves and predators. These are the ocean s unpredictable governing powers, deadly forces that have brought terror and destruction throughout history. Each episode explores a different deadly force while mapping its awesome past and contemporary presence throughout the Pacific, Atlantic, Indian, Southern and Arctic Oceans.