It's reef lobsters to the rescue when Kwazii's Gup-B breaks down; the Octonauts launch a determined search for an elusive giant squid.
The crew pursues crustaceans who've hijacked an Octopod; Captain Barnacles and Kwazii don walrus disguises to recover Peso's stolen medical kit.
A school of flying fish takes off with Professor Inkling's book; a narwhal comes to the Octonauts' rescue when arctic ice grounds the Octopod.
A treasure map leads the Octonauts to an incredible octopus; the crew tries to help an urchin and a carrier crab get along.
An albino humpback whale comes to the Octonauts with a serious case of sunburn; a group of remipedes helps Shellington find his way out of a cave.
Fiddler crabs help the Octonauts get a beached orca back into the water; the crew tries to get three blobfish to safety before a volcano blows.
A decorator crab with sticky fingers has been taking the Octonauts' things to outfit his shell; Dashi winds up inside a whale shark.
The Octonauts trace their ruined equipment to a trio of cookiecutter sharks; Shellington gets caught in a huge jellyfish bloom.
Life's like an undersea rodeo when Barnacles and Kwazii ride some sailfish; Peso travels to the "Midnight Zone," where he meets a vampire squid.
Fear drives a school of humuhumu fish into the Octopod's waterworks; Kwazii mistakes an enormous spider crab for an actual spider.
The Octonauts must trek through a kelp forest to find their Gup-B sub; Tweak and Peso try to help a hermit crab come out of his shell.
A hungry pilot fish comes in handy when the Octonauts run into a whitetip shark; music is the key to saving a pod of stranded beluga whales.
The captain gets creative when a snot sea cucumber invades the Octopod; the Octonauts race to save a leatherback sea turtle from a giant whirlpool.
Slime eels stand between Kwazii and pirate treasure; orcas come to the rescue when Captain Barnacles and Peso are lost in the Arctic Sea.
The Octonauts comb the ocean to help a lost sea star find its home; Peso needs a helping hand when he gets caught in a giant comb jelly.
The Octonauts cross paths with a snapping shrimp; Peso's little brother, Pinto, shadows him on a rescue mission to save Shellington and Dashi.
The Octonauts let an elephant seal molt inside the Octopod; the Octonauts help a lost sardine who's looking for her school.
A migrating young eel needs the Octonauts' assistance on her journey upriver; the Octonauts team with dolphins to save a sickly coral reef.
While seeking pirate treasure, the Octonauts meet a parrotfish; electric torpedo rays help the Octonauts jump-start a powerless Octopod.
The Octonauts explore the "Midnight Zone" and discover a new worm species; the crew comes between two blue whales who are trying to communicate.
The Octonauts try to help a seahorse find its missing mate, who is about to give birth; the crew becomes caught between two groups of anemones.
A cuttlefish that can change shape has stolen Captain Barnacle's Octocompass; the Octonauts help a lemon shark find his way back home.
Kwazii looks after a baby dolphin who follows him home; the Octonauts meet a see-through spookfish while trying to rescue Peso from a trench.
Dashi takes a picture of an oarfish that's unbelievably long; a shipwrecked Peso and Kwazii meet a fish who can walk on land.
Ravenous marine iguanas devour all the Octonauts' seaweed; the Octonauts come to the aid of an injured dwarf lanternshark.
With his friends cheering him on, Peso competes in the annual Iron Clam Competition and goes up against a formidable adversary.
Professor Inkling invites the Octonauts to his childhood home for the holidays, only to find that his octopus nephew is now endangered.
Peso must perform an emergency fin bandage on a hungry great white shark; a poisonous sea krait lays her eggs in the garden pod.
Kwazii and Peso have their hands full baby-sitting a bunch of penguin chicks; Kwazii finds a mysterious, unbreakable coconut.
The Octopod is attacked by a colossal squid; when a mouth-brooding jawfish father loses his eggs, the Octonauts help return them to him.
In search of a mythical sword, Kwazii explores a shipwreck guarded by three swashbuckling swordfish; the Octonauts clean up a beach after a storm.
Barnacles, Kwazii and Peso venture back inside a whale shark to retrieve a puffer fish; the Octonauts land in trouble while helping a young manta ray.
A timid sperm whale must conquer his fears to save Peso from a giant clam; Peso and Kwazii venture down to the midnight zone to help a hurt creature.
A bowhead whale helps the Octonauts save a group of narwhals; the Octonauts help a group of algae-eating fish stand up to some aggressive damselfish.
The Octonauts travel deep down the Amazon River in search of a lost city -- and Kwazii's long-lost grandfather, Calico Jack!
The Octonauts use magnets to try to stop a meteor; the Octonauts help two young leafy sea dragons who were separated from their father.
Running out of air, Barnacles struggles to free his paw from a giant clam's mouth; the Octonauts try to recover an important vial of medicinal algae.
When he's carried away by a cyclonic waterspout, Kwazii finds himself stranded; a gigantic saltwater crocodile wanders into freezing waters.
Hungry gulper eels and undersea tremors threaten Inkling and Kwazii; the Octonauts transport a pair of invasive lionfish back to their native habitat.
The Vegimals' plans for a Christmas feast aboard the Octopod are interrupted when the Octonauts are all entangled in a gigantic blob of sea snot!