The Abyss Stares Back

The Abyss Stares Back is the fourteenth episode of Season 1, and the fourteenth episode overall.

Synopsis
"While diving into a rare 'blue hole', a sinkhole in the middle of the sea, strange things begin to happen to the Nektons. They are seeing things that surely can't exist - or can they?"

Plot
A professional diver named Ken is exploring a newly discovered blue hole when he sees something zip by him at high speed and is able to snag a picture. Quickly returning to his boat he leaves a message for Will, describing what he saw as human.

On the Aronnax Will receives the message, surprised since he hadn't heard from Ken in years and that he's not the easily spooked kind. Kaiko knows the area as a large kelp bed that has apparently died off and Ant believes that what Ken saw was a mermaid. Upon reaching the area instead of Ken the Nektons find Nereus in a boat and he comes aboard, Nereus explains that he sent Ken home with some "associates", he then shows them the photo Ken took which is blurry and their unable to see what the figure is. Before heading to the hole to investigate Nereus looks at the Chronical of the deep where he finds a legend he remembered which says "the hole in the sea that hides a mystery" and "the abyss stares back".

The Nektons take the Jetboat out to the hole, Ant brings Jeffrey along. Ant, Will and Fontaine dive toward the hole. As they dive they encounter a supposed Sabretooth Herring, a fish that should have been extinct for millions of years. They also find another member of Jeffrey's species (Ant puzzled since they shouldn't be in these waters). Ant suddenly sees a figure speed by him and is unable to catch it, when Will and Fontaine catch-up to him Ant describes the figure as about his size looking like a child, with no other dive boats within range Kaiko heads back to the Aronnax to get the Rover to explore further. Ant suddenly sees that Jeffrey is gone and they dive deeper to find him, Will and Fontaine both see humanoid shapes and chase after them through two tunnels while Ant stays, both are unable to catch up but Will finds a Lemurian symbol, while searching Ant encounters "himself".

After a brief encounter the other Ant swims away and Kaiko tells every one to return, as Ant rambles on about what he saw Nereus wants to know more about the Lemurian symbol Will found, he matches it to all the others they've found recently claiming it to be 6000 years old. With Jeffrey still missing the Nektons and Nereus head down in the Rover to find him, when they do find him they see he's made some "friends" who look unusually similar in appearance. As Jeffrey swims around them the other Ant appears in front of them and they all see him, they chase him through one of the tunnels but as they round a bend he disappears and they hit a dead-end, as they search for a way out they suddenly see another Rover in front of them with all of them inside it.

Amazed at what's before them the Nektons try to say something to the others, Ant believes this to be time-travel and that they are seeing their future selves, but Nereus remembers the Chronicle "the Abyss stares back". Ant then realizes it's like a mirror since he saw himself and Jeffrey saw one of himself two and Will realizes the figures he and Fontaine chased were themselves as well, but Fontaine notes that their were more than two Jeffrey's and they all saw them. Will now wants Nereus tell him if theirs anything else the Chronicle states but Nereus says their isn't but he does note that the other Rover now appears to be alive, Ant then has an idea and tells Kaiko to turn off the Rover lights, when she turns them back on dozens of small creatures appear and come together to take the shape of the Rover. They all recognize them as the Mimic Octopus but an entirely new sub-species, noting how they all work together to create whatever they can morph into (unlike the already known Mimic Octopus which can only copy animal shapes and works alone). Suddenly more Octopi appear and start take the form of more Rovers, Will realizes their camouflage is predatory.

The Nektons back away slowly only to find that the way they came in is gone. The octopi then herd them to another dead end before taking the form of boulders to trap them there, they then start to squeeze in on them slowly crushing them. As the canopy starts to break Ant remembers the lights and tells Kaiko to turn them off which makes the Octopi separate, when Kaiko turns them on again she guns it to the exit only to get trapped again, Suddenly Jeffrey appears and is able to separate the Octopi long enough for the Rover to get back to the surface.

As they return Kaiko calls the World Oceans Authority to make the area a no-access protected-zone as well as to replant the kelp bed, Nereus agrees that nobody else should find what's down there Nereus leaves shortly afterward.

Trivia

 * This is the first episode in which none of the Knights appear.