Steve Backshall goes in search of the super-giants of the seas on this Deadly Adventure. Starting on the Californian coast he gets too close for comfort with elephant seals, as the huge males battle it out on the beaches, hoping to impress the females. Driven on by a fascination with ocean super-giants he heads to South Africa to witness the deadly tactics of great white sharks as they hunt. And finally, in the Caribbean, he tracks down the loudest animal on the planet - the sperm whale. But by swimming with these monsters of the sea, Steve discovers that they are actually gentle giants.