The Dweller in the Depths

An ancient energy-draining creature is loosed beneath Cybertron, threatening every Transformer.

On Cybertron, the Autobots have just successfully activated Perceptor's new power core, which should be able to triple the planet’s energy reserves. A short distance away in their ship, the Quintessons watch, disgusted by the success and progress of their creations. One Quintesson unveils a plan to release the Dweller, one of the early biomechanical experiments called Trans-Organics that were developed by the Quintessons that predate the creation of the Transformers. Unable to even perform rudimentary assignments, the Trans-Organics were unstable monsters that were eventually sealed away in a hibernation chamber deep within Cybertron.

On Chaar, Galvatron is lamenting his Decepticon troops' incompetence when the Quintessons beam down to talk. The Quintessons inform Galvatron about the Autobots' new power core but purposely give him the wrong location. Galvatron, Cyclonus and the Sweeps arrive on Cybertron, and break into the tunnel that leads below, soon pursued by Ultra Magnus, Arcee, Kup, Springer, and Wreck-Gar.

In the planet's lowest levels, the Decepticons uncover a chamber full of strange organic pods, but no power core. Realizing they've been tricked, a furious Galvatron blasts the chamber's machinery... releasing the Trans-Organics from their long slumber! The motley horrors tear into the Decepticons, then turn on the Autobots when they arrive moments later.

Leaving the Autobots to deal with the creatures, the battered Decepticons flee to another chamber, searching for a way out.. only to encounter the most powerful of the monstrous experiments: The Dweller, a giant energy leech that drains living creatures of their energy.

In quick order, the Dweller drains several Sweeps, all the Trans-Organics (which vaporizes their organic parts, leaving nothing but a few mechanical bits behind) and Wreck-Gar. When Springer tries to rescue him from a storage pod on the monster's back, the zombiefied Junkion drains his energy too: all the victimized Transformers have been turned into shambling energy vampires! Kup is lost to the vampire horde as the battle continues; Arcee and Magnus finally manage to escape.

Lost in the maze of chambers and tunnels in the dark depths of Cybertron, unable to find their way back to the surface, the Decepticons find their numbers quickly whittled down by the Dweller until only Galvatron is left (it doesn't help when Galvatron starts throwing Sweeps at it to buy time for himself.)

Even hunted by the subterranean nightmare, Galvatron can't resist the chance to attack the two last Autobots when he comes across them. Their struggle is soon interrupted by the arrival of the Dweller, which dislodges Galvatron's cannon and knocks him out. Arcee turns Galvatron's weapon against the Dweller, blasting through a wall... but rather than continuing the fight, the Dweller heads toward the power core.

The two Autobots make it back to headquarters where they update Rodimus Prime and Perceptor on the situation, the energy vampires bursting in right behind them. Perceptor determines that the vampires are suffering from a unique form of energy depletion and that a power surge should restabilize their levels. The Autobots form a chain with Perceptor at the end, who plugs himself into the console and they inject the crowd of vampire with an energon surge. The surge returns the Autobots and Decepticons to normal. Cyclonus, Scourge, and the Sweeps quickly escape and rejoin Galvatron in fleeing the planet.

—Galvatron in his rage demands to know from Scourge and the Sweeps why he isn't victorious. He takes out his frustrations on them until the Quintessons arrive.

—Galvatron and the Quintessons as the latter manipulate the Decepticon leader as part of their new plan to retake Cybertron

—Wreck-Gar saves Ultra Magnus from the Dweller's energy-draining web, only to get trapped in it himself and be drained.

—Springer frees the energy-drained Wreck-Gar from the Dweller's rear pouch.

—Galvatron sacrifices another Sweep to the energy vampires that are approaching.