Treasure of the Islanders is the fifteenth episode of the first season of the animated series.
"The nektons are in a race against time and pirates to get a treasure that could save an entire island from extinction"
Ant, Will and Jeffery arrive at the floating black market in the Jetboat while Fontaine is in the Rover in case things get ugly, they arrive at the boat where their supposed to meet Dolos but are instead grabbed by a tentacle.
Dolos arrives and tells his pet octopus Hydra to let Will (and eventually Ant) go, once freed Will discusses a map that Dolos has for sale, Dolos says it's the map to the fable treasure of the Morocu islanders after which Ant shows a video from the leader of the island stating their island barren and their people homeless and the treasure could save them, Dolos says he already offered the map to the islanders but it was a shame they couldn't "afford" it, so Will and Ant buy the map for them. As this is happening Hydra tries to grab Jeffery out of the Jorange but Jeffery bites his tentacle instead making Hydra grow a fear of Jeffery. As Dolos leaves Will asks him why he didn't go after the treasure himself Dolos simply says it was a waste of time and also there was the curse! then leaves to an adjacent boat. Upon examining the map Will and Ant finds that it reads "he who disturbs the treasure must surely know weathering starvation and extinction".
As they leave they encounter Hammerhead and Finn leaving with the same map, realizing Dolos sold them one too is now a race to the treasure. Will and Ant make it back to the Jetboat but Mad Madeline has anchored it to the dock which Ant doesn't notice and when he sets off the engine is ripped out, with the Jetboat disabled Madeline jumps back onto the Dark Orca as it leaves, Fontaine arrives in the Rover and brings Will and Ant back to the Aronaxx. After returning Will leaves a message for Dolos to call him back, suddenly the Dark Orca appears on sonar heading straight for them but Ant notices something is off and thinks its a trick, the sonar pitch ends up going right through them with the Orca itself not appearing at all, they then receive a threating message from Hammerhead who states he will turn the Aronaxx into scrap metal if it gets in his way again. Will then tells Ant to show Hammerhead how it's done, Ant takes the Rover out and covers it in kelp making it seem like a sea monster, this works in scaring the pirates and they turn back, Ant then starts a competition with Fontaine to see who's better at messing with pirates.
While looking at the map in the study Ant notices an inscription on the map border, immediately after he receives a call from Dolos who's responding to Will's earlier message, Ant tells him about the inscription which reads "peal the skin of the fruit to find the treasure within the treasure" when he asks Dolos what it means Dolos (after a long pause) suspiciously says it means nothing and ends the call. The Nektons then receive a mayday call from a lifeboat, Ant and Will take the Rover to location but their ambushed by Madeline (wearing a wig) and Finn and are handcuffed to the boat, Madeline putting the wig on Ant, she and Finn then steal the Rover. Ant and Will are rescued by Fontaine and Kaiko after which Fontaine using uses the Rover remote control to bring it back (giving Finn and Madeline a rough ride in the process), Finn and Madeline are brought aboard but the Dark Orca appears directly under the Aronaxx and Finn manages to steal Fontaine's communicator before swimming out back to the Orca.
The Dark Orca then zooms ahead but Kaiko easily overtakes them however Hammerhead fires a net into the Aronaxx's engine disabling it, Will and Fontaine take the Swamp Knight and the White Knight out to fix it while Ant takes the Shadow Knight out (with Jeffery) and places a scrambler on the Orca's hull causing it to go off coarse. Despite freeing the net from the engine a racket on a reduction gear comes loose preventing the Aronaxx from moving, knowing they may not have time to fix it Ant asks Kaiko to give him the grid coordinates for the treasure so he can get it first Kaiko agrees but tells Ant to be careful. Ant finds the treasure which turns out to be a large urn but as he arrives he sees Dolos land a sea helicopter on the surface above knowing he will take the treasure Ant tells Jeffery to do a "special ops mission". Kaiko is able to fix the engine and they head to Ant's position. As Dolos is about to grab the urn with suction arms Jeffery swims to the surface and scares Hydra making him squeeze Dolos as this is happening Ant swaps the urn for a large rock which Dolos takes still thinking it to be the treasure. As Ant examines the urn the Dark Orca suddenly appears!
Ant grabs the urn and attempts to flee but Madeline deploys the Orca's "bubble" (a large air pocket) trapping him, Jeffery is able to swim out, once trapped the water is pumped out and Hammerhead, Finn and Madeline are simply lowered to the ground, refusing to give up the treasure Hammerhead orders his men to "pry" it off him but shortly after the Aronaxx arrives and Will demands Hammerhead to release Ant and step away from the urn but when Ant sees a symbol on the urn he says the pirates can have it. Ant removes the top of the urn which inside contains seeds that all belong to the plants made extinct on Morocu remembering the reading on the map "weathering starvation and extinction" it all adds up but Hammerhead doesn't believe it and thinks Ant stole the real treasure. Dissatisfied Hammerhead prepares to destroy the urn as compensation but are stopped by Will and Fontaine who use the threat of removing the air pocket to force the pirates back, in a last ditch attempt to stop them Hammerhead tries to ram the Aronaxx with the Orca but Kaiko sabotages the rudders forcing them to retreat.
Back on the Aronaxx the leader of Morocu is extremely grateful to the Nektons for finding the treasure and even want to carve a giant statue of Will. Kaiko is still confused as to why Dolos went after the treasure believing he'd already figured out it was just seeds Ant agrees but says that when he told Dolos about the inscription "peal the skin of the fruit to find the treasure within the treasure" it made Dolos realize there was more to it, it is then revealed that the urn is made of solid gold which is why Ant opened it to stop Hammerhead from getting to close and discovering it. This now means the islanders can replant their home and have money for the future.
- This is the first time the "bubble" appears.
- The Shadow Knight legs are shown to have removable plates.
- This is the only time Hydra is referred to by name.