Cameraman Bob Cranston spends most of his time getting close to our ocean's most dangerous predators and he's noticed something very strange is happening Off the coast of Baja California (Mexico), great white sharks are congregating in shallow water and they are not feeding on their usual prey of sea lions. And in the frigid waters of the Pacific Northwest, six gills sharks have started hunting in a very shallow 50 feet of water. Strange behaviour. Cranston needs to get close in order to solve the mystery and has specially designed Shark Sonics - a device to attract sharks to his camera. The idea is that instead of chumming the water with fish blood, the Sonic device emits low-frequency waves, like a distressed fish, to attract the sharks. The big benefit is that you can then turn it off to study the sharks as they then calm down and stop thinking about food! Follow Cranston’s journey as he gets up close and free-dives among them without a cage!