The Return of Dagon Arc

The Creature From Beyond is Liberated
Underground, the Forever Knights accidentally break the seal that was imprisoning to a legendary and dangerous creature of another dimension. The dangerous creature gets hold of the minds of everyone present, turning them into his slaves. Meanwhile at the same time as the creature is liberated, in Bellwood's convalescent home one of his tenants reacts and leaves, the elder is called by the nurse as "Old George".

Another faction of the Forever Knights is going to investigate the site of the events, but in the place Ben, Gwen and Kevin appear, both decrees make a truce to look for the creature and for the missing Forever Knights. After crossing the streets in search of the creature they find it in an alley possessing a policeman who attacks them. The Creature also possesses Gwen and Winston (the young squire), but it does not manage to possess Kevin since he was in his form of metal, Gwen manages to escape, whereas Winston is kidnapped by the Creature. All are released, though, after Ben as NRG makes a hole with the creature inside and Gwen creates another seal to trap it. It is revealed at the end of the end of the episode that the Lucubra planted something in the people it possessed, when Winston's eyes turn green again.

Paradox's Warning
After defeating Eon, Paradox gives Ben a warning. "Beware Old George. Beware the creature from beyond".

The Disappearence of Area 51
At the Area 51 base, Old George appears and defeats all of the security guards. Seconds later, Area 51 disappears.

The Return of the First Knight
Old George is finally identified in The Purge, where it is discovered that Area 51 was turned into his new headquarters. He is recognized as the First Knight, a medieval warrior who founded the Forever Knights a thousand years ago. He unites the factions into one group and he assigns Driscoll as his second in command. After Driscoll lost a battle with Ben as Ultimate Spidermonkey, he goes to inform his failure to Sir George. He expects anger from The First Knight, but George is unfazed. He informs Driscoll that he is leaving on a quest, and that he will be in charge until then. He informs Driscoll to prepare the knights for when he returns, for "The Battle of a Hundred Lifetimes." And with that, he leaves.

Return of Vilgax
It was a dark and stormy night at a carnival where there is a man running a freak show stand. A man is selling flyers for the group called the Flame Keepers Circle. He accidentally drops the papers, and when he picks them up, he looks into the tent and sees who he thinks to be Diagon, though he is actually Vilgax. Later, a group of Esoterica come, beat up the manager of the freak show, and liberate Vilgax. Later, Julie joins the Flame Keepers' Circle because she thinks that they will bring peace to the world, but Ben and Kevin are skeptical. Julie gets very mad at them and storms off. Later, Ben as ChamAlien sneaks into the building and checks out a door that he was curious about, and when he opens it, much to his surprise, is his arch-nemesis, Vilgax. Vilgax tells Ben that after his ship blew up, he washed up onto the shore and the circus man found him. He was regaining his health in the tank when the Esoterica found him and took him here. Now he is treated like a god. He tells Ben that he will return to his empire and Psyphon and then destroy the Earth. Ben reveals that Vilgax's empire fell because they thought he was dead. This Annoys Vigax so he calls his Esoterica to attack Ben, claiming he is an enemy of the Diagon. Ben attacks them as Big Chill and Ultimate Big Chill, but surrenders when Conduit Edwards threaten Julie. Ben reveals that this is Vilgax, not Diagon, and she gets away from Conduit just as Gwen and Kevin arrive. Ben shatters Vilgax's tank with Echo Echo and leaves. When the Esoterica are repairing the tank, one of them questions whether Ben was telling the truth about Vilgax. Vilgax replies that when he's done with the Earth: "You won't even recognize it".

The Origin of Ascalon
The episode starts off from where the previous episode ended, Ben, Gwen and Kevin watch as Sir George retrieves his sword and tells them to let the Diagon come.

George speaks to Ben and his team about the Diagon when Azmuth comes and says that the sword was his, that he created it and he wants it back. He tells Ben to take it so Ben transforms into Fasttrack and fights George with the help of Gwen and Kevin, but fails so he transforms into Humungousaur. Sir George uses the power of his sword to transform Ben back to his human form, George creates a portal with his sword and leaves the cave.

The Battle of a Hundred Lifetimes
As Ben and Gwen are with Kevin in his garage as he finishes making his car submersible, they are attacked by the Esoterica, who are destroying anyone who stands in the way of Diagon's return. They fight off the Esoterica with Ben as Four Arms and Gwen is able to capture one of the members with her mana, as they can't teleport through mana. Kevin interrogates him and they are able to find out that the Flame Keepers' Circle is planning to let Diagon into this dimension.

The team go to the Flame Keepers' Circle headquarters and find out that none of the members are there. Ben transforms into Clockwork and uses his powers to show that they have all left to free Diagon. Meanwhile, Sir George is at the Area 51 fortress, rallying the Forever Knights to fight Diagon.

When Ben, Gwen and Kevin arrive at the location of The Seal with the Rust Bucket 3, they find the Forever Knights and the Flame Keepers' Circle at war, and neither side is winning. Ben asks them to land the Rust Bucket 3.

Ben tries to tell the Knights that he is here to help but the Knights refuse to listen and attack them. They force Ben and the team back into the Rust Bucket 3, and Ben transforms into Goop to fight them. After a difficult fight they are able to defeat them, and Gwen creates a mana shield at the door of the Rust Bucket 3, which was not closed, to prevent the other attacking Knights from coming in.