Under the sea, under the sea! Darling it’s better down where it’s wetter, take it from me.
We open in the ocean, where Wilykit and Wilykat are swimming. Wilykit is once again using peer pressure on Wilykat, trying to get him to keep swimming even though he’s concerned about an approaching storm.
Wilykat heads for shore while Wilykit swims further out. But a giant metal frog surfaces behind her!
The frog opens its mouth and water rushes in, pulling Wilykit with it. She’s swallowed whole. We cut inside, though, and learn that Wilykit isn’t hurt. In fact, she meets a short, bald man with funky goggles who claims that he came here to ask the Thundercats for help.
Back outside, we see that the frog is actually a bipedal robot, and it emerges from the water, chasing Wilykat.
Wilykat flees, nearly getting stomped several times. Also, he apparently stopped to put his boots on when we switched camera angles, since he was barefoot before when he was running on the beach.
The giant frog robot has also scared some unicorns, and Wilykat jumps on one of their backs in order to escape more quickly. He rides the unicorn back to Cat’s Lair (which seems to have been repaired remarkably quickly from the damage it suffered last episode), where Lion-O and Snarf are outside. Wilykat is freaking out about the “water-giant” that swallowed Wilykit, and eventually gives Lion-O enough of the story that he wants to see what’s going on for himself. Lion-O jumps on the unicorn with Wilykat and they gallop off back toward the frog.
They dismount and sneak up on the giant frog. Wilykat wants to get the Thundertank and blast it, but Lion-O doesn’t want to blast it “for no good reason”. Wilykit thinks the “it ate Wilykit!” reason is pretty good.
As they sit and watch, the frog opens its mouth and the bald guy climbs out on a rope ladder.
The bald guy has a big picnic-style basket. He pulls a blanket out of it and lays it on the ground. He then pulls a big bouquet of flowers out of the basket. It he trying to put the moves on Wilykit? Ragardless, Lion-O and Wilykat knock him down and interrogate him.
As they rough him up, Wilykit calls down from above and warns them not to hurt Dr. Dometone. It turns out that he is “one of Third Earth’s great scientists, thinkers, and gentlemen”. She also explains that the whole “swallowing” thing was her fault, since she swam right into Herky’s mouth (Herky is the frog robot). We cut to Cat’s Lair, where Dr. Dometone is explaining the premise of the episode.
Dr. Dometone is the guardian of the Great Oceanic Plug. “Centuries ago a fissure developed in the surface of the sea floor. … Unless it was sealed the ocean would empty into the very core of the earth, and put out its fires. In the greatest engineering feat of all time the hole was plugged.” The Plug is being attacked, and there’s a good chance it will be pulled out. Why would anyone do that? Well, that’s quite simple, really. A thousand light years away, the planet Blue Plunder uses for fuel a common mineral found under the sea on Third Earth. They’ve sent a salvage expert named Scrape to drain the sea and just grab the rocks. And Scrape flies around in a badass eel-themed spaceship.
Dometone explains that since the Plug was built, two robots, Hercules and Samson, have defended it.
Dometone took Hercules (Herky, for short) to get some supplies, and Scrape took that opportunity to attack Samson with his eel ship. And it turns out it’s an electric eel themed spaceship.
Since the eel defeated Samson so easily, Dometone and Herky hightailed it out of there and came to the Thundercats for help. Without the supplies that Dometone was bringing, the crew in the Plug will soon starve. And if the crew tries to get out, they’ll provide the opportunity for Scrape to get in and pull the Plug. Lion-O, Wilykit, and Wilykat get into Herky to go to the Plug immediately, while the other Thundercats stay behind to work on an emergency rig in case they need one.
We cut to the Plug dome, where two of the technicians are discussing the situation. They haven’t seen the eel for a while, and are out of food. They don’t think Dometone will return, so they figure they may as well try to go for help now, before they starve.
They elevate the dome’s observation tower, and still don’t see the eel. One of them volunteers to suit up and head for the propulsion sub. Unbeknownst to them, though, the camera pans over to show that the eel has been lying in wait! The technician is launched in his little purple submarine, but the eel pops up and swallows it.
Furthermore, the eel bursts through the observation tower and is able to stick its head into the dome. Herky arrives, and they see the eel sticking halfway out of the dome.
Inside the dome, Scrape swims out of the eel’s mouth in some diving gear. He gets on the intercom and warns the crew of the Plug dome to abandon ship before he pulls the Plug. That’s nice of him.
The crew complies immediately, and a swarm of the little purple submarine escape pods blast out of the place. Dr. Dometone is ready to throw in the towel, but Lion-O tells him there’s still time. He wants to know what Dometone’s plan was to defeat Scrape, to see if they can still put it into action. The plan involves Lion-O and Wilykat dressing up like sharks.
Dometone gives Lion-O a “grounding cable” which will be able to neutralize the charge of the electric eel ship. Scrape, meanwhile, has detected Herky and pulls the eel ship out of the dome in order to go and fight him.
Lion-O and Wilykat swim out in their shark suits, with Lion-O letting the cable play out behind him. Lion-O plans to try to loop the ground cable around the eel’s tail when it passes. Scrape notices the “sharks”, which he finds odd since he didn’t expect any in the area. He puts his eel into high gear, just to be safe.
The eel speeds away, and Lion-O misses his chance. The eel ship and the robot frog fight!
Dr. Dometone calls out advice to Herky from inside, but it doesn’t seem to make much difference. The eel wraps itself around Herky and starts constricting.
The eye-windows of the frog and the eel line up, and Scrape is able to see through them to talk to Dometone and Wilykit, so he uses the opportunity to gloat with bad puns. Dometone advises Herky that Scrape has “exposed the eel’s neck.” Aren’t eels mostly neck? Anyway, Herky takes his corner-man’s advice and grabs the eel behind the head and starts shaking. Scrape is thrown away from his controls so he can’t activate the electrifier.
Lion-O swims up and, using the grounding cable like a lasso, attaches it to the eel just in time.
Scrape hits the switch, but the electric charge is diverted into the cable and Herky is unharmed.
Scrape isn’t ready to give up yet, though. He goes down to the little purple submarine he had the eel swallow earlier and gets in.
Lion-O returns to Herky, but Wilykat is dawdling outside. He sees Scrape’s submarine exit the eel. Wilykat, still in the shark suit, tries to shove the sub off-course to give Lion-O time to come help. Scrape, however, deploys a net from the sub to capture Wilykat.
Lion-O decides he needs some more help. “Thunder, thunder, thunder, Thundercats, HO!” Tygra, Cheetara, Panthro, and Snarf hop into the Thundertank and start heading for the Plug dome. Inside the dome, Scrape has sealed the windows and pumped the room dry (although he gives no indication about how he stops water from pouring in the giant eel-shaped hole in the roof). He has Wilykat tied up, and explains that when he pushes a button it will be the first time in seventeen centuries that the Great Oceanic Plug has moved.
With the Plug open, water starts to flow into the Plug dome and down the fissure. However, the water level outside the window falls far too quickly for Scrape to believe the entire ocean has emptied. Panthro gets on the communicator and explains that they’ve enclosed the dome in a compressed air bubble. “You’re an engineer, you can understand that,” Panthro says. Well I’m an engineer and I certainly don’t.
Scrape realizes his plan has been foiled, but doesn’t plan to go down easily. Panthro orders Tygra to “hit the vacuum suction button.” Somehow, this causes Scrape to be lifted off his feet inside the airtight dome, be thrown through the glass window that’s presumably strong enough to handle the pressures of the ocean floor, and get sucked into the mouth of the Thundertank.
In the coda, back at Cat’s Lair, Wilykat is reminding everyone that he wanted to use the “shoot first, ask questions later” technique on Herky at the beginning of the episode, which would have killed Wilykit and Dometone and doomed the planet. Lion-O explains that Scrape was turned over to Mandora for transportation to the Gray Prison Planet. Panthro explains that Dometone has fixed the Plug dome, and put in a hotline to Cat’s Lair. Tygra, however, is only concerned about dinner. This gives Wilykit and Wilykat an opportunity for a “joke” about having fish for dinner, which involves Wilykat getting back into his shark suit. The other Thundercats start throwing tableware at him, and Snarf (carrying the real dinner) gets caught in the crossfire.