From spy dolphin to spy tuna and turtle, for the first time an underwater menagerie of spy creatures infiltrate the secret world of dolphins. Swimming alongside some of the most captivating and clever animals on the planet, these new spies are always on the move - catching the waves with surfing bottlenose dolphins and speeding with a megapod of spinner dolphins. From the team at John Downer Productions that brought you the unforgettable Penguins - Spy In The Huddle, this is one of the nation's favourite animals seen as never before. David Tennant returns to narrate.