The Ultimate Enemy: Part 2 (Version 2)

The episode starts off from where the previous episode left off. The Team, Sir George, Vilgax and Psyphon look out through a hole in the cave to see the gigantic Diagon hovering outside after breaking the Seal. They head outside to confront him. Diagon claims that he won't need to fight the Team and George, calling Vilgax to do away with them. However, Vilgax has vanished, leaving George to comment Vilgax is wise for knowing that Diagon will be defeated. Undeterred by this, Diagon simply summons droves of Esoterica in Vilgax's place and has them begin attacking, with their focus solely on George. Gwen and Kevin decide to keep them busy so George can fight Diagon.

Ben, seeing Jury Rigg is no match for Diagon, transforms into Way Big. However, before Way Big can finish his quip, Diagon cuts him off, gloating how he believes he will defeat him and conquer our dimension. Way Big finishes his quip and transforms into his Ultimate version, growing to a fraction of Diagon's size. Jumping on Diagon's face, Ultimate Way Big begins pummeling him, much to Diagon annoyance. Tossing Diagon into a dam and destroying it in the process, Ultimate Way Big begins shooting cosmic rays and discs at his foe, accidentally destroying some property when he loses his balance momentarily. However, none of Ultimate Way Big's attacks cause any significant damage to Diagon.

Annoyed by Ultimate Way Big's attempts to stop him, Diagon creates a small acid storm over Ultimate Way Big, harming him long enough to cause the Ultimatrix to time out, leaving an bloody Ben on the ground.

Elsewhere, Gwen and Kevin have become overwhelmed by the seemingly endless amount of Esoterica, leading Gwen to cast a protective shield to block them. Diagon appears before them, leading Gwen to think Ben may be deceased. However, Kevin assures her that Ben might have simply just changed back. George declares Ben's sacrifice will not be in vain and resumes fighting Diagon, giving him several slashes to the face while Gwen and Kevin resume fighting the Esoterica.

Back at the dam, Ben recovers and transforms into Wildmutt, then into Ultimate Wildmutt to head back to the battle. Arriving, Ultimate Wildmutt helps Gwen and Kevin defeat the Esoterica, defeating all of them.

Meanwhile, Vilgax impatiently tells Psyphon to hurry with the machine's preparations. However, Psyphon tells Vilgax that he needs to properly adjust the device as it is not like absorbing just the powers from a being like he had previously done. Vilgax then threatens him to make sure it works, something Psyphon takes well.

Outside the cave, Chromastone saves George from Diagon's laser by using his energy absorbing ability, and then shoots ultraviolet rays to Diagon, giving George an opening. However, when George fails to land a hit on Diagon, Chromastone fires again, yelling that he's out of energy. Gwen asks how much energy he can hold, and when answered "a lot", Gwen charges him up with mana, allowing Chromastone a larger blast. However, Diagon has become annoyed with the heroes' constant attempts to stop him and knocks Chromastone to the ground. George attempts to make another attack on Diagon, but however, Diagon sends a red bolt of lightning down from the sky that zaps George. Weakened, George reverts to his old man form, dropping Ascalon, and kneeling on the ground. He then turns completely grey and begins to blow away in the wind as a cloud of dust.

Diagon relishes in his victory over George, proclaiming that his conquest of this dimension will soon come to fruition. However, Vilgax comes into view with Psyphon and the machine, declaring that if anyone is to rule this universe, it's going to be him; he also plots to take over Diagon's universe as well. Diagon then attacks Vilgax, planning on destroying his "weapon". However, his laser beams are absorbed into the machine as it keeps drawing in his power. Psyphon explains that under normal conditions, the device simply drains a being's powers. However, since Diagon's very being is made of power, he gets absorbed by the machine. Upon completely absorbing Diagon, Vilgax demands his power be given to him. Ben tries reasoning with Psyphon, but he doesn't listen. Upon gaining Diagon's powers, Vilgax takes a form similar to him and shoots laser beams at the team, leaving nothing but a smoldering crater where they were.

However, it is revealed Gwen teleported everyone to the Plumbers' Mount Rushmore base. Ben theories that they have a couple of days before Vilgax figures out they aren't dead and how to properly use his powers to find them. However, he is proven wrong the minute he stops talking as Vilgax's voice demands they come out and face him, sending the Esoterica to attack them. However, Gwen activates the base's defense system, warding off the mindless drones. Annoyed, Vilgax resumes his previous form and rips off the Washington face from the monument, disabling the defense system.

Once inside the mount Rushmore fort, Vilgax begins tearing apart the base, knocking out Gwen and Kevin. Faced with Ben in one final stand-off, Vilgax wonders what tricks will Ben use this time, only to see him grab the Ascalon and become covered in knight's armor; Ben decided not to use the Ultimatrix, having figured out how to use the sword. Vilgax fires energy blasts at Ben, but he reflects them back at Vilgax with Ascalon. They both charge at each other, and in a flash of light, Vilgax is reverted to his normal form; Ben absorbed Diagon's power into Ascalon. When Vilgax questions what he'll do with Diagon's power, Ben tells him that he'll change the Esoterica back to normal.

However, Vilgax says that with the Ascalon, the Ultimatrix and Diagon's power, he could rid the universe of evil for good. Ben finds this interesting, but a recovered Gwen and Kevin question if he should actually take moral advice from Vilgax. Julie and Ship arrive, asking Ben to stop. Stressed with the choice with what to do, Ben screams and see many worlds in his eyes. Julie says that the worlds were splintered a long time ago. Ben ceated a new world out of the old ones, turning everyone back to normal, just as he said. Julie kisses Ben, something he says is worth giving up all that power, as Vilgax dies.