Megatron has been called away from his evil scheming by Soundwave to show him something very interesting - an underwater city! An underwater city that Megatron, of course, imagines must generate oodles of energy - oodles of energy that can be harvested! For evil! In no time at all they make their way to this underwater city and marvel in its wonderful glory, but Starscream, ever the brainiac, flies straight for it and crashes into an invisible force field he didn't see, for obvious reasons (it was invisible).
The head honcho of Sub-Atlantica comes out
and introduces himself as Nergill, communicating with them telepathically and
therefore demonstrating how super his mental power is, and when Starscream
believes it to be inferior to his firepower, blasts the Seeker out of the sea.
Nergill hoped his guests weren't violent jerks, and Megatron only proves that
further by blasting the rock behind them and showering the creatures in debris.
Megatron laughs at anyone who dares oppose him, but admires their warlike spirit
and considers them allies, where after the Sub-Atlanticans have a little
conversation that the others can't hear, they decide to join forces.
Nergill shows them about his place, showing that the place is literally swimming in abundant energy, but the citizens of his city must remain deep beneath the sea. Megatron, of course, just plans to stay on the good side long enough to take this energy from them. He is kind enough to free the people of their need to stay underground by stabilizing the energy by keeping it in energon cubes, and soon Sub-Atlantica will rise above in the world of conquest!
At Autobot HQ, Bumblebee, Hound and Spike
are playing some good ol' football against the Dinobots, of all opponents. It
doesn't go too well and before anyone can score Slag squashes the ball, which is
just as well as Optimus needs everyone back inside for a briefing. Apparently
strange energy readings have been coming from the deep Atlantic, and he needs
volunteers. Hound and Bumblebee see it as more fun than football, and Wheeljack,
Brawn and Spike decide to tag along too.
The four Autobots proceed to deny the laws of common sense by being in car mode and proceeding to swim through the ocean, drifting through like the most elegant of fish, where Spike begins filling them in on the whole Atlantis tale and how this is probably connected to it. Nergill and the other Sub-Atlanticans show up and lay mild smack down coupled with laser fire, soon followed up by the Seekers, Laserbeak and Buzzsaw raining pain.
Spike suggests they head back to inform Optimus of this, but they're in no position to retreat effectively with everything that's firing at them, so they head into an alcove which Wheeljack blasts the wall of, sealing his buddies safely inside. Wheeljack is promptly taken prisoner by the Sub-Atlanticans, who are supposedly given orders by Nergill to be wary of the Autobot, but Soundwave decodes this scrambled instruction to reveal that Wheeljack's going to be experimented on to make weapons against his fellow Autobots and the Decepticons!
The island is once more brought to the surface via use of rockets, allowing it to open fire on Bumblebee, Hound and Brawn (who happen to have never had their escape from the cave shown or mentioned), but they get to shore just dandy. Bumblebee finally contacts Prime and informs him of the massive shit they're in, wherein the island is heading straight for Washington D.C.! All of the Decepticons but Starscream fly out there first, allowing Nergill to gloat aloud and unscrambled to himself how he will soon rid himself of these metal tyrants that are supposedly allies, which, of course, Starscream overhears.
While the Autobots make their way to Washington D.C., the Decepticons and Sub-Atlanticans have already arrived and scared away the humans, allowing them to build a force field generator right in the centre of the location and keep themselves secure. The Autobots manage to get in just before the force field is fully formed, allowing them to exchange fire and giving Prowl and Hound the opportunity to moonwalk on water.
Meanwhile, Bumblebee and Spike arrive at
Sub-Atlantica and get in underneath the force field. Nergill is testing his
magnetic dysfunction ray on Wheeljack where it's working like a charm, though
Starscream steps out and does a very bad job of trying to get it off him, only
succeeding in getting a dose of it himself. Nergill wanders off, pretty chuffed
with himself, while Starscream attempts to sap energy from Wheeljack's innards,
just in time for Spike and Bumblebee to stroll in and knock the bastard against
Nergill arrives in Washington, followed by
Bumblebee, Spike and the operational Wheeljack, while Prowl, Brawn and Hound
face off against Skywarp and Thundercracker. Brawn has the wise idea of lassoing
Thundercracker, which does absolutely nothing except let the poor guy fly in
circles helplessly until Priem shoots him out of the sky. Nergill steps in with
his electronic dysfunction ray, and proceeds to disable the four Autobots with
it, prompting Megatron to actually praise a subordinate for once.
Wheeljack and Bumblebee arrive just in time to see all their chums get shot down, but since Wheeljack is well aware of how unpleasant the electronic dysfunction ray is, they're in no position to challenge Nergill or attempt repairing their comrades. So who else do they call in? The Dinobots! They're frustrated at how dippy the Autobots can be at times, but as usual, they pop on over to Washington to save the day.
In the meantime the Sub-Atlanticans anticipate the chance to strike back against the Decepticons, while the Decepticons are thinking the very same regarding their man-fish companions, except they've the visual bonus of having Megatron seated on the Lincoln memorial throne as it's said. The Dinobots arrive outside the force field and set about demolishing it like glass, somehow.
They immediately set about blasting Laserbeak and Buzzsaw out of the sky, clobbering the reactivated Starscream and gloating over Optimus Prime's near-corpse until Megatron arrives, ready to rip Grimlock a new poop chute. The Decepticon leader and Dinobot commander set about with some fisticuffs, Nergill stepping in to blast the Dinobot but lacks a clear shot to do it without risk of blasting Megatron. He then just decides to zap both of them...
Until Starscream punches him to the ground, swiping the electronic dysfunction ray off him, which is soon knocked out of his grasp by Bumblebee and Wheeljack and into the hands of Grimlock, who bends it like rubber. Like all cartoon electronics, this just reverses whatever it did and all the Autobots are up again in tip-top shape. Megatron's mighty pissed at Starscream for what he allowed to happen, while the Sub-Atlanticans and Decepticons retreat, but not without a bit of needless vandalism.
By wrecking the Washington monument! Prime dashes over to keep it aloft, and after another dose of gloating, the Dinobots add their muscle to getting it vertical once more and repair it good as new. And after Mr. Lincoln has gotten his seat back, they Autobots roll out for Sub-Atlantica to wreck it up something fierce.
Back at the island, Megatron attempts to make Nergill accept the fact that he was a bit of a treacherous git, but he makes a good save by pointing out the fact the entire Autobot army is approaching, including the Dinobots, who set about racking up some major damage. Megatron attempts another rematch with Grimlock, but you can imagine how well that fares.
Nergill is none too pleased with how much damage his city is taking, and drops underground to detonate the energy stockpile so he can rid himself of these mechanical menaces. Spike, Bumblebee and Wheeljack follow after, along with Rumble and Ravage to stop the Autobots, who are just in time to witness Nergill attempting to blow the place sky high, giving Rumble the opportunity to make use of his pile drivers to delay the aquatic fiend.
He's a determined fiend, though, and he climbs up the tower once more to detonate it with Wheeljack scrambling after, and despite holding him down, Nergill still blows up the energy stockpile. The Decepticons make a hasty retreat while Prime is alerted of this and tells the others to retreat while he heads below to rescue his comrades.
Grimlock is found safe and sound, and Bee and Wheel are still in one piece with Nergill captive, so everyone's accounted for, giving them no reason to delay swimming to the surface as the place goes up in flames.
As they arrive at the top to witness the city sinking beneath the waves once more, to join the myth of Atlantis once more, they realise that Nergill's vanished! Prime is under the belief that they've seen the last of the watery foe, but can only wish he could say the same about Megatron and the Decepticons.
Cars swimming - positively absurd. Planes swimming - I have no complaints. I don't understand myself sometimes.