Phil Torres and Heather Amaro travel 5,000 miles west of the U.S. to the remote Marshall Islands, home to the world's largest shark sanctuary, where apex predators are exhibiting highly aggressive behaviors and erratic swimming patterns. Between 1946 and 1958, the United States military detonated 67 nuclear bombs around the island, raising questions about their lasting impact on marine life. Now, the team dives into these dangerous waters to investigate reports of "mutant" sharks and uncover whether atomic blasts could be to blame.

Global explorer Josh Gates travels back in time and dives into the history behind some of the world's most infamous shark encounters, from the earliest known shark attack to the mystery surrounding the shark feeding frenzy faced by sailors following the sinking of the USS Indianapolis in remote waters. He also investigates the legendary "Stronsay Beast," a mysterious creature that washed ashore in Scotland in 1808, long thought to be a sea monster. But could it in fact be the remains of a massive shark?

In celebration of America's 250th anniversary, wildlife biologist Forrest Galante embarks on a nationwide quest to find the nation's most bizarre and dangerous alien sharks – from glowing swell sharks to elusive sawfish – proving the ultimate shark adventure is right here at home.