Since ancient times the sea has been man's playground, and his pathway to new lands and new continents - but also his savage enemy. Linked to an ITV series of the same name, this exploration of the violence of the ocean combines science and human stories, dealing with topics which range from ice-caps to the tidal bores of China, and with man's dramatic relationship with the sea. Waves and tides, tidal waves, freak tides, rip-tides and whirlpools - what are they and why do they occur? How do humans interact with these phenomena? What is the lure of the sea? These are among the questions addressed, as well as mysteries of the deep: submarines, deep-sea exploration, ocean resources, deep-water life, diving, volcanic hazards, the Bermuda triangle, cyclones and hurricanes, icebergs and ice-breakers.