Hello Kitty meets Star Trek under the sea! Dive in for adventure with these much-loved picture book characters.The Octonauts are a crew of cute animals who love to explore the big blue ocean. From their underwater base, the Octopod, the eight intrepid friends are always ready for fun and excitement!When the Octonauts go on holiday to the Great Reef City, they're shocked to discover that the brightly-coloured coral reef has turned white. Whatever can have happened? And is it true that the Great Reef City is haunted? It's up to the Octonauts to solve the mystery and save the reef!