The Test

The Test is the eighth episode of Season 1, and the eighth episode overall.

Synopsis
"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 this unusual test?"

Plot
Nereus speaks to the other members of the Guardians Proteus, Glaucus, and Tethys, about how the Nektons could be a major help in finding Lemuria, but Proteus is skeptical of their abilities. Nereus decides to let the Nektons prove themselves by having them do a "test".

Meanwhile, Will is studying symbols only to discover that the scroll is gone! After searching all over the Aronnax, Ant finds Nereus in the cargo bay with the scroll and brings him to the study. Nereus explains that the scroll is called the Chronicle of the Deep. He also explains that one of the symbols represents an item known as the Ephemychron which as he describes is an ancient navigational computer that was used by Lemurians. Nereus tells the Nektons that he tried to find a piece of the Ephemychron long ago but failed and now asks them to find it. The Nektons agree and head out.

Will, Ant and Fontaine take the Knights to search a maze of reefs where the piece should be located. Before leaving, Will tells Kaiko to keep an eye on Nereus as his strange behaviour makes Will suspicious. As they search the reef, the currents become stronger sweeping them all over the place and leading them to a maelstrom. Unable to get ou,t Will uses the Swamp Knight's cables to attach to the others. Using the combined power of the Shadow and White Knight, Ant and Fontaine create a counter-revolution and they all manage to get out.

Back on the Aronnax Nereus unlocks Will's safe (despite Will changing the password). As the trio push on they encounter very murky water and lose sight of each other and disappear from the Aronnax's sonar. When they ask Nereus for help he simply says "sometimes to see we need to stop looking" . Ant decides to turn off his Knight's power and let the current move him. The three eventually meet back up and find a way out of the murky area. When they ask Nereus if he knows of anymore "surprises" ahead, Nereus says that he never made it past the murky water and doesn't know of anything else ahead.

The three reach the site where the piece should be but instead they find three abnormally large jellyfish. Suddenly the jellyfish attack and begin draining the Knights' power revealing that they're actually robots. Kaiko demands answers from Nereus but Nereus believes that the jellyfish shouldn't be there. While Kaiko prepares The Rover, Nereus secretly calls Proteus and tells him that someone from within has compromised the tests but is caught by Kaiko. After passing the maelstrom and the murky water, Kaiko helps the others destroy the jellyfish, after which they believe Nereus (due to his evasiveness) can't be trusted. As they start to leave Ant notices one of the broken jellyfish sink beneath the seabed.

Ant dives down through the mud and discovers a shipwreck that Nereus mentioned earlier as well as the piece of the Ephemychron but as he's grabbing it he becomes stuck on the tongue of some creature that begins to close its mouth. Realizing that Ant is missing the others turn back to look for him. Ant calls to them on his radio telling them that he's beneath them but they don't understand. Nereus realizes where Ant is and takes control of the Rover and dives through the mud. He and Kaiko manage to save Ant and they all return to the Aronnax. Upon returning the Nektons are amazed by the design of the piece and Nereus believes they can find the rest.

Nereus returns to the Guardians HQ where Proteus informs him the he was unable to find the saboteur, and warns Nereus that some answers can be dangerous for both him and the Nektons.

Trivia

 * Although listed as the eighth episode, Netflix listed it as the ninth episode of the season instead. This also happens to the episode Fossil where it is listed as the eighth episode on Netflix instead of the ninth.
 * This makes sense as the Swamp Knight is properly introduced in Fossil.