Captain Barnacles runs into a long-lost friend - an arctic fox named Professor Natquik - in Antarctica. They must work together to prevent a group of penguins from falling into an ice chasm. Join the Octonauts for these and other exciting adventures both above and under the ice! Episode synopses OPERATION DEEP FREEZE Captain Barnacles runs into a long-lost friend (an arctic fox named Professor Natquik) in Antarctica, where they must work together to prevent a group of penguins from falling into an ice chasm. EMPEROR PENGUINS The Octonauts journey across a dangerous expanse of ice to help a penguin mother get back to her family. TIGER SHARK Tweak must help her friend Sandy the sea turtle escape a hungry tiger shark. LONELIEST WHALE The Octonauts follow a strange song to a lonely humpback whale, who is alone because he doesn't sound like the other whales! SUNFISH The Octonauts must help a giant sunfish who can't swim straight, before it hurts other sea creatures and itself. COELACANTH While exploring a dark and spooky cave, the Octonauts discover the fossil of a powerful, prehistoric fish but it may be more than just a fossil.