We are back off the coast of San Francisco where an unexpected killing challenged the great white shark's supremacy as the ultimate predator. We return with the whale-watchers who witnessed a stunning act of nature as a killer whale rose to the water's surface with a great white in its mouth. The outcome left biologists mystified but now, with the help of a team of experts, we re-examine this extraordinary incident, and reveal an astonishing new perspective between the ocean's two top predators.

NGC counts down the top ten most terrifying sharks from around the globe. Using a specially designed "Crittercam", we'll dive into the shark world and see everything from an intimate moment between nurse sharks, to a bull shark on the prowl for its next meal. Then, we'll take you to a Mecca for great white sharks, and see them feed on one of their favorite snacks seals. From the scary, to the ugly, and the downright freakish, we'll show you what's really lurking in the darkness.