Secret of The Omnitrix serves as the series finale of the original series.
Ben battles Dr. Animo as either Heatblast, Eye Guy, or XLR8 when he suddenly is hit by a DNA wave that puts the Omnitrix in Self-destruct mode. Tetrax the Petrosapien senses that and comes to Earth to tell Ben about it. Ben, Tetrax and his pilot, Gluto, travels along the galaxy to find Azmuth, the Omnitrix's creator. Gwen soon appears on the ship to help Ben. After some time of searching on Incarcecon, Ben, Gwen and Tetrax get themselves in a street-fight, where Ben spots a female Chimera Sui Generis, Myaxx, who first claims that she created the Omnitrix. Actually, she was only Azmuth's asisstent and directs Ben and the others to Xenon, where Azmuth lives. Then, Tetrax's ship, the "Resolute" was intercepted and boarded by Vilgax and his drones, but they were stopped by Ben, Gwen, Tetrax, Gluto, and Myaxx. In that action, Gluto was assumed dead. When they got to the planet, they were attacked by a group of wild Floraunas, where Gwen was taken and assumed dead. After Ben's sadness, Tetrax told him the story about him bringing Vilgax the final element he needed to destroy his home planet. Even though turning into an alien would only accelerate the self-destruct, Ben turned into Cannonbolt to break in Azmuth's lair, but Azmuth refused to help them. Ben then looked outside and sees Vilgax, Sixsix and their massive army of drones. Azmuth removed the main part of the Omnitrix, but Ben, Tetrax and Myaxx still fought. Soon, it was revealed, that Gwen and Gluto were still alive and also helped Ben. Soon, Azmuth put the Omnitrix back on and gave Ben Way Big, a gigantic alien called a To'kustar. Ben then transformed into Way Big, defeated Vilgax's army of drones, grabbed Vilgax and threw him into space, returning to Earth and finding out that zombies were attacking the mall.
- Ben and the gang meet up with Tetrax again.
- Ben and Gwen first meets Azmuth.
- Ben first transforms into Way Big.
- Ben and the gang learn about the Omnitrix's self destruction sequence.
Omnitrix alien debuts
- Ben Tennyson
- Gwen Tennyson
- Max Tennyson
- Vilgax's Drones
- Heatblast or Eye Guy or XLR8 (Version Differs)
- Greymatter (Selected alien was Stinkfly)
- Wildmutt (Selected alien was XLR8)
- Way Big
- Ben: You have to tell me how to work this thing!
- Azmuth: Don't you want to figure out it on your own, like a true hero would?
- Ben: Um, not really.
- Azmuth: (laughs) I like that boy.
- Way big: WHOA! Check me out! I'm not just big, I'm WAY BIG!
- Tetrax: Is he okay?
- Ben: Mom, I don't want to go to school...
- Gwen: Yeah, he's okay...
- If you look at the background of Incarcecon, you can see some or all of our solar system planets meaning it is not far away from Earth.
- Many characters keep saying "who knew?".
- Hoverboard's name is revealed to be Tetrax Shard.
- When Cannonbolt breaks Azmuth's bio-suit and Azmuth comes out of it Cannonbolt asks "He's really a Grey Matter?". Myaxx answers "Who knew?". This is confusing because she most likely doesn't know what Ben calls his aliens.