Steve tracks down the ultimate aquatic athlete. Taking mega-migrations around the Atlantic and Pacific oceans, the blue sharks are ocean Olympians. Steve catches up with a couple of these bolts of blue off the Californian coast, before heading to the Shark Lab to reveal how these canny creatures rely on their liver to provide buoyancy, and hitch a ride on ocean currents, allowing these athletes to make mega-migrations across the great oceans.

Steve meets a shark that is the master of moves. The Caribbean reef shark has lightning-quick reaction times and is one seriously flexible fish. Steve heads to the Bahamas in the Caribbean to swim alongside them, before finding out the secrets to their flexibility in his Shark Lab.

Steve meets a night-time ninja. The whitetip reef shark has a cool and calm character by day, but after dark they turn into highly honed hunters. Scouring the reef, they search out prey that's hiding away in coral caves. Steve gets a closer look at them off the coast of Malaysian Borneo and gets under their skin in his Shark Lab to explain how they can fit where other sharks can't.