After the Junkbot shoots the Omnitrix and it begins glowing neon-blue, an imprisoned Vilgax explains it is now a gateway through which the Fulmini Empire will invade Earth, but the only way to stop them is from within the Omnitrix, so Ben must team up with the ultimate baddie if he is to save his planet.
Ben doesn't believe Vilgax about the Fulmini. Vilgax explains that in order to save the planet, he has to go inside the Omnitrix. He tells Ben that the signal released by the robot Ben made in his sleep established a gateway. A gateway through which the Fulmini will invade Earth.
Ben asks Vilgax what the Fulmini has to do with his watch going all weird. Vilgax explains that it's the real name of the alien race he calls Shock Rock. Vilgax tells them that the gateway is inside the Omnitrix. Team Tennyson huddles up and decides whether to trust Vilgax or not. Ben asks why does he care about Earth all of sudden. Vilgax interrupts telling them that he doesn't, but he fate of the Universe, and the Omnitrix are at stake. He knows the device better than anyone, and he's the only one that can help stop the invasion. The Tennyson's agree to team up with Vilgax.
Vilgax asks for the Omnitrix. Ben puts his arm up and Vilgax starts messing with the watch. Ben questions what he's doing, but Vilgax tells him he wouldn't understand. Ben transforms into Grey Matter knowing he'd understand. Vilgax asks to continue. Vilgax tells him that he's trying to access the transport access panel. Grey Matter suggest the acronym 'tap'. Vilgax manages to transport themselves into the device. Afterwards Max leaves to make some pasta, figuring that it's going to be a long night. Gwen sits and waits.
Inside the Omnitrix, Ben lies on the floor after being transported into Omnitrix. Vilgax awakens him and compliments his resilience. Ben asks where are they. Vilgax tells him that their inside the loading chamber. He explains it's where the alien's genetic material is combined with Ben's DNA. Ben notices a pod that should be Upgrade's DNA. Vilgax finds it strange as well. Ben asks Vilgax how does he know about the tap. Vilgax tells him that their is many things that he knows about the Omnitrix that Ben is unaware of. While they argue, Fulmini soldiers arrive. Vilgax begins fighting them off, telling Ben to transform. Ben questions how he will transform without the Omnitrix. Vilgax tells him that the Omnitrix is key to his DNA, and tells him to make contact with one of the pods. Ben jumps into a pod, transforming him into Four Arms. Ben and Vilgax both fight off the soldiers, while Ben switches from Four Arms, to Cannonbolt, to XLR8, to Wildvine. Ending off his constant transformations with Heatblast. Eventually one of the Fulmini soldiers manages to escape through the portal, leading it to Earth. Vilgax blames Ben for letting the soldier escape to Earth.
Back on Earth, Max presents his pot of pasta to Gwen, right before the escaped Fulmini soldier arrived. Gwen and Max run off. Max grabs a part of the robot, and shoots at the soldier. Back inside the Omnitrix, Vilgax and Ben continue fighting off the Fulmini. Vilgax demands they push the Fulmini back, and lock down the chamber. Ben (as Heatblast) complains knowing he won't have access to the DNA pods. Eventually Vilgax locks down the chamber. Vilgax and Heatblast comes up to a few paths in order to find the portal. Heatblast runs through each one, finding Fulmini soldiers in each path. Heatblast holds off the Fulmini while Vilgax tries to open up another way. Eventually the Omnitrix security protocols are set off, causing deadly foam to flow through the watch. Eventually a door is opened up, and Vilgax and Ben jump through.
Vilgax and Heatblast looks at the Fulmini army, noticing the huge amount of soldiers. Ben reverts back to human unexpectedly. Ben yells out that he's totally useless now, and Vilgax agrees. Ben says for an evil genious, it took Vilgax a while to open the door. Vilgax tells him that he didn't open it, and Ben asks who did. A voice from behind them reveals that he helped them.
Ben asks if it's Upgrade, and the figure steps out, revealing himself to be Glitch. Glitch assumes they have questions, but for now, they should run.
Ben and Vilgax go inside the Omnitrix to stop the Fulmini invasion.