The Octopod is grabbed by a colossal squid. The Octonauts are unable to break free due to the hooks on the ends of the squid's tentacles. Fortunately the arrival of some sperm whales turns the squid from hunter to hunted.
Adelie Penguins: While Kwazii and Peso have their hands full babysitting a bunch of Adelie penguin chicks, Captain Barnacles must rescue the chicks' parents from a perilous sea storm! Coconut Crabs: Kwazii finds a mysterious, unbreakable coconut, so the Octonauts seek out the help of some large, island-dwelling coconut crabs to open it.
Kwazii is driving the GUP-B when he notices he is hit by an unbreakable coconut and it has the symbol of his grandfather Calico Jack so then Kwazii, Captain Barnacles, Peso, and Tweak get a family of coconut crabs to help him open it.
It's Sea Snakes on an Octopod when a poisonous sea krait lays her eggs in the garden pod, just as Captain Barnacles has to navigate the ship past a treacherous whirlpool.
Scared Sperm Whale: A timid sperm whale must conquer his fears and dive deep down to help the Octonauts release Peso from a giant clam. Long Armed Squid: Peso and Kwazii venture down to the midnight zone to help a hurt creature, but what they find is a shipwreck "haunted" by a spooky-looking long arm squid.
Flying Swords: In search of a mythical sword, Kwazii explores a pirate shipwreck that happens to be guarded by three swashbuckling swordfish! Fiddler Crabs: The Octonauts help clean up a beach after a storm, but things get complicated when the resident fiddler crabs hijack the Gup-D!
The Octonauts help a young manta ray find the secret manta ray feeding grounds, but when they finally locate it, the Octonauts become caught in the middle of a dangerous feeding frenzy!
When he's carried away by a cyclonic waterspout, Kwazii finds himself stranded in the desert-like open ocean with a triggerfish who's made her home underneath the damaged Gup-B.
Manatees: Running out of air, Barnacles struggles to free his paw from the mouth of a giant clam, while simultaneously directing his crew in a delicate Manatee rescue operation. Mimic Octopus: The Octonauts recruit a shape-shifting mimic octopus to help them recover an important vial of medicinal algae from a moray eel's lair.
Gulper Eels: When hungry gulper eels as well as undersea tremors threaten Inkling and Kwazii, Dashi uses the new, multi-purpose Octo Max Suit to rescue them. Lionfish: The Octonauts get more than they bargained for when they use the Octopod to transport a pair of invasive lionfish back to their native habitat.
After his Gup is struck by lightning, Captain Barnacles gets trapped by a giant clam but doesn't call for help as he wants the others to go help some manatees at risk from a thunderstorm.
Triggerfish: When he's carried away by a cyclonic waterspout, Kwazii finds himself stranded in the desert-like open ocean with a triggerfish who's made her home underneath the damaged Gup-B. Saltwater Crocodile: When a gigantic saltwater crocodile wanders into freezing waters, the Octonauts must figure out how to get the predator back to his warm water home - without anyone getting hurt.
Hungry gulper eels as well as undersea tremors threaten Inkling and Kwazii and get trapped by boulders. So Dashi uses Tweak's newly built "Octo Mach-Suit" to rescue them.
