The team are fighting a red Techadon Robot. Kevin reveals that the Techadons are mass-produced battle robots and the fact that they are not a single being just like the team had previously thought. Lodestar pulls the Techadon Robot apart and the gauntlet starts to escape, but Kevin destroys it. Just as the Techadon is about to be destroyed, Lodestar transforms back into Ben and the Omnitrix says that it must return to Primus. Ben tries to transform, but the Omnitrix keeps saying that it must return to Primus. Ben and Kevin wonder who Primus is. The Omnitrix teleports Ben to a jungle planet, and Gwen and Kevin jump in just in time. They emerge next to a stream of green lava leading to a volcano. A group of various blue alien wasps drink it and fly to the volcano. The alien wasps, Voliticus Biopsis, attack the group and while Kevin and Gwen fight them, but Ben cannot transform. The Omnitrix scans the Voliticus Biopsis and determines that it has returned to Primus. The Omnitrix disconnects from Ben and the Voliticus Biopsis bring it to the volcano.
The team heads to the volcano through the jungle and Ben is concerned that Azmuth is going to be mad at him for losing the Omnitrix. They come across destroyed Voliticus Biopsis with scorch marks that were destroyed recently. Ben is disgusted by the jungle. A creature in the green lava watches the team and Gwen makes a mana bridge over it when the creature grabs Ben and pulls him under. Kevin leaps in and Gwen grabs them both with mana, splashing the lava all over and they enter into a tunnel in the volcano and go inside. The team see Humungousaur and Vilgax fighting and they believe that Humungousaur is Primus. Ben says that he and Vilgax have to be working together and Vilgax defeats Humungousaur and he transforms back into Azmuth, surprising the team. Vilgax throws a rock at Azmuth, who transforms into Rath and catches it. Rath attacks Vilgax and they fight and Gwen and Kevin run out to help Azmuth, telling Ben to stay hidden. Vilgax defeats them easily and takes the Omnitrix from Azmuth (after he is defeated and transforms back from Rath).
Vilgax demands that Azmuth tell him how to use the Omnitrix. Azmuth refuses and Vilgax tries to transform, failing. Ben goes to Azmuth. Azmuth tells Ben that the Omnitrix is now Vilgax's and that the team has to leave so as to prevent them from falling into his hands. Vilgax tells Ben to come out or he will kill Gwen and Kevin. Azmuth tells him not to, but Ben doesn't listen and reveals himself. Vilgax chains the four up while he tries to work the Omnitrix. Gwen and Kevin have headbands that prevent them from using their powers and the floor opens, revealing the green lava. Azmuth explains that the lava is actually the Codon Stream, and that Primus is the planet. He created it to contain the Codon Stream, which contains the DNA of every sentient species in the universe, collected by the Voliticus Biopsis. The Omnitrix wirelessly connects to Primus and accesses its DNA. When Vilgax arrived, Primus summoned Azmuth and the Omnitrix. Vilgax overhears and threatens to destroy Primus if he isn't told how to use the Omnitrix. Ben volunteers to tell him and, despite Azmuth's protests, transforms Vilgax into Goop. Ben takes Goop's Anti-Gravity Projector and deactivates it, immobilizing him. He then takes the Omnitrix back, which transforms Goop back into Vilgax, and puts it on. Vilgax attacks Ben and Ben transforms into Cannonbolt. Cannonbolt and Vilgax fight and Cannonbolt knocks Vilgax into the Codon Stream, narrowly avoiding falling in himself and Cannonbolt transforms back into Ben. Azmuth says that Vilgax is not defeated and he emerges, having grown to an enormous size. Ben transforms into Way Big. Way Big and Vilgax battle in the Codon Stream and Way Big throws Vilgax into space. Later, Azmuth tells Ben that Vilgax will return to normal soon and he reluctantly allows Ben to leave with the Omnitrix.
Kevin: I got this! (jumps in after Ben) Gwen: (panicking after a while) Ben! Kevin! (uses her mana to burst them out) Kevin: (after landing on a tree with Ben) What part of "I got this" do you not understand?
Ben: Azmuth. Everything's going to be okay. Azmuth: Did you just "there, there" me?
Kevin: (after Ben defeated Vilgax, following Azmuth, and speaking to Gwen about the incident when Ben gave in with Vilgax) Couldn't you have acted way over the top when Ben gave in to Vilgax? (pretends to act like Gwen, putting up a girly voice) Ben, noooooooooooo!!! Gwen: (defending herself) I was just trying to help Ben trick Vilgax! Kevin: Sure. Keep telling yourself that! (Gwen gave Kevin an angry look)
Vilgax: (after seeing Azmuth with Ben, Gwen and Kevin, trying to figure out the secrets of the Omnitrix) This world is important to you, eh, Azmuth? More important than your own life? Or those of these children? That leaves me an intriguing option. Tell me how to activate the Omnitrix, or I'll destroy the whole planet. Ben: No! Azmuth: Ben! Ben: Azmuth can't help you. He's just trying to protect me. I'm the only one who knows how to work the watch! Azmuth: That's not- Kevin: Button it, genius.
Vilgax: You'll work the Omnitrix for me? Ben: (thinking of an agreement) If you let my friends go! Vilgax: We have an agreement! You teach me to operate the Omnitrix, and I'll free your friends! But you, Ben Tennyson, will die. Ben: (thinking of something else in mind, putting up an act) All right. I guess I have no choice! Gwen: Ben, noooooooooooo!!!!! Ben: (shouts to Gwen) I know what I am doing Gwen! Kevin: Since when? Vilgax: (breaks Ben's chain and throws him) Show me, human! Ben: (starting to teach Vilgax, as much to Kevin's, Gwen's and Azmuth's shock) See, when you turn the dial, you have to be pushing in at the same time. (stops at the hologram of Goop and presses it) Azmuth: (closes his eyes since the light of the Omnitrix is too strong) Ben, noooooo!!!!! Vilgax as Goop: (does some experimenting with Goop's power) The power is unbelievable! I can do anything! Ben: Almost anything! (snatches Goop's gravity projector and deactivates it, double-crossing Vilgax) Vilgaxas Goop: (tries to attack Ben, but falls to the ground before he can) What did you do? (straining to get up) I can't move! Ben: (cunningly) I know. I turned off Goop's artificial gravity! (snatches the Omnitrix from Vilgax and puts it on his hand, now trying to show off) Who's the hero? Gwen and Azmuth: (together and annoyed by Ben's act) You are. Ben: Everybody? Kevin: (also annoyed and rolling his eyes) You are. Ben All I ask for is a little credit.
Ben: Azmuth! Kevin: Quick! Chew through our chains! Azmuth: I am not a rodent! Kevin : Could've fooled me...
Way Big: (grabs Vilgax's hand, whacking his face repeatedly with it) Stop hitting yourself, stop hitting yourself, stop hitting yourself! Kevin: Heh heh heh heh! Classic.
Ben: So are we okay again? I mean, does this make up for- Azmuth: Damaging my Omnitrix? No. I shouldn't even allow you to leave with it. Ben: But will you? Azmuth: You are welcome, Ben Tennyson.
Azmuth: Give me a minute... I'm a little out of practice... Ben: It's Azmuth! Gwen: We should've known! The Omnitrix kept saying it was looking for its creator! (Vilgax throws a boulder at Azmuth, who transforms into Rath and catches it) Azmuth(as Rath): Let me tell you something, Vilgax, conqueror of ten worlds! Azmuth will defeat you! Azmuth will hunt you down even though you're standing right here! You are no match for the awesomeness of Azmuth!
Naming and Translations
While here, Humungousaur (Azmuth) and Vilgax are en par in strength, in Vengeance of Vilgax: Part 2, Vilgax beats Ben as Humungousaur, even in his giant form.
Although it is shown that Azmuth does not intend to forgive Ben, he allows him to keep the Omnitrix, but cannot trust him anymore.
When Vilgax changes into Goop, he still talks in his own voice.
When the Omnitrix came off of Ben and went onto Azmuth, Azmuth turned into Humungousaur, with the same appearance as Ben as Humungousaur, yet when Vilgax put on the Omnitrix and turned into Goop, he looked a little different than Ben as Goop.