Early November, pregnant giant hammerheads arrive off Bimini, in the Bahamas and Shark Week's Dr. Tristan Guttridge wants to know why? And he and his team even perform the world's first ever ultrasound on hammerheads to find the answers.

Greg Skomal & Joe Remeiro return to Shark Week to study the area that brings thirty species of sharks, the Gulf Stream. They will focus on three sharks that can out-swim, out-think, and out-compete all the others makos, great whites, and porbeagles.

Paul De Gelder returns to Shark Week with Dr. Jonathan Werry and Andy Casagrande to unlock the mysteries of the new great white hotspot, Isle of Jaws. And on their journey, they make a startling discovery that causes them to re-think everything.