Episode 1
A dragon hunting expedition leads Ant to an ancient scroll that holds clues to an amazing mystery. But his family are trapped by the dragon and only Ant and Jeffrey can save them. And Jeffrey's a fish.
Episode 2
The Dark Orca pirates attack. They believe the Nektons have a rare treasure aboard their sub. With pirates on one side and an erupting undersea volcano on the other, the Nektons will have to get creative to escape.
Episode 3
An artificial intelligence programmed to run the sub and protect the Nektons tries to stop their rescue mission because it's too risky. When they try to shut her down, she takes over completely to save them from themselves.
Episode 4
Will and Ant are retrieving an item from the deepest part of the ocean, but it is not what they were told. They've been duped. And now there's a stowaway on the Aronnax, trying to take control of it.
Episode 5
Are aliens stealing things from a Japanese island and dragging them underwater? Ant believes that's perfectly reasonable. The Nektons investigate and find something even more dangerous. But can they escape?
Episode 6
Someone just stole the rarest tortoise in the world and the Nektons are searching for it. But the man who stole it secretly wants to capture them too. They're walking into a trap, but really, there's no other way.
Episode 7
Captain Hammerhead has captured the Nektons aboard his sub! But his rusty vessel is about to sink. The Arronax could save them all, but first, Hammerhead would have to free the Nektons-and that's not exactly in his character.
Episode 8
To find a piece of the mysterious Ephemychron, the Nektons have to fight off whirlpools, zero visibility and giant robotic jellyfish. Is Nereus doing this to them? If not, who is really behind all these obstacles?
Episode 9
Huge prehistoric crocodiles still inhabit an underwater cave system the Nektons are exploring. Ant shouldn't have bonded with that baby croc-its enormous mother doesn't take kindly to kidnappers, and now she's after him.
Episode 10
Ant and Fontaine hunt for one of the rarest ocean creatures: the colossal squid. But it turns out to be smarter than anyone thought and thinks the Nektons look tasty. Can the Aronnax survive being pulled down very, very deep?
Episode 11
Media superstar Devil Daniels - Monster Hunter is hunting a sea creature that he believes is a menace, but the Nektons want to protect it. To make matters worse, the public are on Daniels's side.
Episode 12
Does a ghost sub haunt the ocean depths? Ant believes it does, but when he actually finds this "ghost sub", the truth is even stranger - and much more dangerous. Ant and Fontaine find themselves trapped - by a ghost?
Episode 13
While diving in a rare blue hole, a sinkhole in the middle of the sea, strange things begin to happen to the Nektons. They're seeing things that can't exist. And where did the exit go? Why is there no way out?
Episode 14
Ant and Fontaine are sure they can control some young fans visiting the Aronnax. But when they have to rescue a whale calf, success depends on them and all the hyperactive kids working well together. What could go wrong?
Episode 15
Dolos has sold two maps leading to the same treasure: one to the Nektons, the other to the pirates. Now it's a race to get there first, and the winner will need to use every sneaky trick in the book to win.
Episode 16
As the Nektons explore a mysterious tunnel behind a huge undersea waterfall, strange creatures and strong currents surprise them at every turn. Everything is not as it seems.
Episode 17
The Nektons are arrested for stealing. Ant and Fontaine escape to prove their innocence, but whoever set them up is already two steps ahead.
Episode 18
Fontaine and Smiling Finn get stuck inside a giant clam as the Dark Orca pirates battle the Nektons for the giant pearl within.
Episode 19
Proteus, leader of the mysterious Guardians, traps the Aronnax in a magnetic field and kidnaps Ant, believing he is the key to finding Lemuria.
Episode 20
Devil Daniels, Monster Hunter, attempts to hunt a siren - a mythical creature whose song lures sailors to their doom.
Episode 21
A fish invades Jeffrey's home on the Aronnax. How can he get rid of it and its bad luck?
Episode 22
The Rover is swallowed by a huge prehistoric shark. Will and Fontaine manage to cling to its gills just inside its mouth.
Episode 23
The Nektons are trying to identify a unique life form. They've never seen it, they've only heard its sound: 'Bloop'.
Episode 24
A weird glowing fish has lured every fish in the area to its bioluminescence, and Kaiko and Will also fall under its spell.
Episode 25
While fighting over Viking treasure, the Nektons take over the Dark Orca. But the pirates in turn take over the Aronnax.
Episode 26
The Nektons explore a floating island and find the final piece of the Ephemychron in a cave. But the island has a terrible secret.
