The Great White Serial Killer returns and it's on a killing spree that may push the California Sea Otter to extinction. Investigators deploy an otter dummy to get a closer look and witness one of the most spectacular attacks in Shark Week history.

Adam Devine and a team of experts found a secret shark lair that may be the world's largest gathering of tiger sharks. To Adam and friends Anders Holm and Blake Anderson, it's the ultimate shark party, and they want to know what makes this party epic.