When one little snail longs to see the big wide world, she hitches a lift on the tail of an enormous whale. Together, they set sail on an amazing journey, past icebergs and volcanoes, sharks and penguins, and the little snail feels so small in the vastness of the world. But when disaster strikes and the whale is beached in a bay, it's up to the tiny snail to save the day.Julia Donaldson and Axel Scheffler's brilliant story of unlikely friendship and life-changing adventure has been brought to life on BBC One in an animation starring Sally Hawkins, Rob Brydon, Cariad Lloyd and Dame Diana Rigg.