After the explosion, Gwen emerges from the rubble unharmed, due to producing a Mana shield, and she sees Chromastone and Spidermonkey get up and run away. Ben emerges from the rubble and sees Goop leave as well. The two are confused and they go to Kevin and are shocked to see that he has mutated into an amalgam of materials and can't transform back into normal. Ben, unconcerned, sees that he is missing the three aliens that escaped in addition to Way Big. Azmuth comes on the hologram and yells at Ben, telling him that he has to recapture his transformations in 24 hours. Gwen can't track the aliens, but Kevin says that they can track their Omnitrix symbols with their badges. In the car, Kevin tries to absorb Gwen's skin, but he still cannot transform back into normal. The team then locate Chromastone on a pier, who is attacking a ride. Gwen says that without Ben, the aliens are nothing but instinct. Kevin attacks Chromastone and discovers that he can transform his hands into weapons, but he is defeated. Ben tries to transform into Humungousaur, but he transforms into Murk Upchuck. Upchuck and Chromastone fight through redirecting the same laser at each other over and over. Gwen shoots mana, but Chromastone sends it towards Upchuck. Kevin knocks Chromastone out and Upchuck captures him back in the Omnitrix.
The team then drive to a forest where Spidermonkey is. Gwen does research and discovers that Vilgax defeated 10 heroes and took their powers. Ben begins to worry about his upcoming battle and then the car gets caught in a giant web. Spidermonkey grabs Gwen and wraps her in web and Ben and Kevin leap onto the web and get stuck. Ben transforms into Brainstorm and Brainstorm and Spidermonkey fight with each other while Kevin frees Gwen. Brainstorm absorbs Spidermonkey into the Omnitrix. They drive to a sewer where Goop is. Inside, Ben finds Goop's anti-gravity disk. Goop then appears and traps Ben. He attacks Gwen and Kevin, sending them flying and bringing pipes down on them. Ben transforms into Swampfire inside Goop and breaks free. Goop runs and Swampfire chases after him. They fight and Goop runs again. Gwen tells Swampfire not to shoot fireballs, but he doesn't listen and the sewer blows up. Swampfire regenerates on the surface. Gwen and Kevin come out, protected by mana. Goop destroys Swampfire, but he regenerates and captures Goop. Later, they track Way Big, but there is not enough time to capture him and get Ben to his fight. Max calls and offers to fight Vilgax for Ben, but Ben declines. Ben says that he'll stall Vilgax until Gwen and Kevin bring him Way Big. Psyphon arrives at the park and says that the battle is being broadcast on all channels and that Vilgax's fleet is in orbit, ready to destroy the planet when Ben loses. Then, Jetray flies in and Vilgax arrives.Vilgax and Jetray battle, but Vilgax defeats Jetray, so he transforms into Big Chill. Big Chill freezes Vilgax, but Vilgax escapes. Vilgax is able to grab Big Chill while he is intangible and electrocutes him. Big Chill transforms into Humungousaur, who grows to full size and fights Vilgax. Vilgax defeats Humungousaur, but Gwen and Kevin arrive with Way Big. Ben scans Way Big and tries to transform into him, but he transforms into Chromastone. Chromastone fights Vilgax, and is winning, but Vilgax shatters him, destroying him and shocking Gwen, Kevin, and Max. Psyphon takes the Omnitrix and hands it to Vilgax, but it regenerates Chromastone into Diamondhead. Diamondhead attacks and defeats Vilgax, forcing Vilgax to yield to Diamondhead. Later, Diamondhead transforms back into Ben and Vilgax is banished from the Earth. Vilgax vows revenge on Ben and leaves along with his fleet and Psyphon. Max tells Ben that he blacked out the broadcast, protecting Ben's secret.
Ben: I'm missing Goop, Chromastone, Spidermonkey, and Way Big. How'd he manage to sneak away?
Ben: This is a job for... Humungousaur! (transforms into Murk Upchuck)' Murk Upchuck: (sighs) Or Upchuck. Upchuck is good.
Ben: Here Chromastone...good Chromastone.(whistles)
Ben: Eww, smells like a sewer in here. Gwen: I'm not kidding Ben, no more sewer jokes. Ben: Smells like a plan to me. (Gwen hits him) Ow!
Vilgax: Ben 10, I've come to kill you and conquer your world. Is now a bad time? Are you ready to die, Ben? Jetray: Can we skip the threats and get to the "fight" part? There's a Sumo Slammers marathon at eight, and I forgot to set the DVR.
(Vilgax swings his sword at Jetray) I'll take that as a "yes".
Grandpa Max: By the rules of the galactic code, as ratified by the Casey-Kelly accords, you have lost this contest. You must leave this world, and never attack it again. Do you acknowledge? Vilgax: I do. But know this, Ben Tennyson. I will have my vengeance upon you. Ben: Sure thing. Get outta here.