Country star Brad Paisley and comedian JB Smoove meet in the Bahamas to attract new fans, Sharks! With Dr. Austin Gallagher's help, they put Brad's musical talents to the test in shark-infested waters to see how sound can attract or repel sharks.

In 2012, Michelle Jewell documented one of the largest great white mating scars ever recorded. Recently similar marks have appeared, leading her to believe this is a possible mating ground and that mega-shark El Diablo has returned to South Africa.

To track down New Zealand's monster great whites, researchers build a submersible designed to look like a shark and pilot it deep into what they believe could be a mating ground - the Holy Grail of shark science.