Naturalist Steve Backshall goes in search of some of the 30-plus shark species that inhabit the British Isles, showing how the big fish in home waters are just as astonishing and mysterious as their global cousins. Along the way he encounters a four-ton basking shark in the Scottish Hebrides and dives with his favourite of all time, the blue shark, off the coast of Cornwall. He also meets scientists and conservationists in Wales who are working to protect endangered species.