Source: http://en.wikipedia.org/wiki/List_of_Ben_10:_Omniverse_episodes
The More Things Change Part 1
Teaser: 5 years ago, Ben Tennyson faces off with a new enemy, Malware.
Main Plot: 5 years later, Kevin and Gwen leave when Gwen takes early enrollment in an Ivy League college, and Kevin moves to be with her. Ben is forced to fight crime alone, but Grandpa Max (Magister Tennyson – the commander of the Earth-base's Plumbers) gives him a new partner, rookie Plumber Rook Blonko. Ben and Rook end up in their first team-up when Mr. Baumann's store is targeted for destruction by three alien criminals, named Bubble Helmet, Fistina, and Liam, as part of their protection racket. However, an intergalactic hunter named Khyber watches Ben from the shadows.
Young Alien Debuts: Four Arms, Feedback (official debut)
Current Alien Debuts: Lodestar, Spidermonkey, Cannonbolt, Bloxx (official debut)
Nemetrix Alien Debuts: Crabdozer (predator to Heatblast)
Part 1 aired as a Sneak Peek on August 1st The More Things Change Part 2
After stopping Bubble Helmet, Fistina, and Liam from blowing up Mr. Baumann's superstore, Ben and Rook discover an underground alien city named Undertown where they discover that Psyphon is behind the protection racket. At the same time, Khyber sends his pet in the form of Buglizard to hunt Ben.
Current Alien Debuts: NRG, Water Hazard, Terraspin, Armodrillo, Shocksquatch
Nemetrix Alien Debuts: Buglizard (predator to Stinkfly)
Parts 1 and 2 aired sequentially for the series premiere on September 22nd
Crasher from Gobots is seen in this 2 part episode A Jolt From The Past
Teaser: Ben Tennyson has to stop the Megawhatts for destroying the grand opening of Mr. Smoothie.
Main Plot: The Megawhatts that Ben fought in his youth come back. This time, they need Ben's help when they are being used as a power source for the villain Fistrick and his gang.
Young Alien Debuts: Stinkfly
Current Alien Debuts: Heatblast, Clockwork, Gravattack (official debut) Trouble Helix
Teaser: Infiltrating the Plumbers' base, Khyber uploads footage of young Ben's encounter with a corrupted Mechomorph named Malware.
Main Plot: Young Ben Tennyson faces Malware for the first time
Current Alien Debuts: Chromastone, Cannonbolt
Young Alien Debuts: XLR8, Heatblast, Cannonbolt, Diamondhead Have I Got A Deal For You
Ben meets an alien con-artist named Professor Blarney T. Hokestar whose miracle elixir is extracted from a small alien called a Screegit that is kept in his lab. When a Florauna activist named Pax convinces Ben to help him free the small alien from the Hokestar's lab, chaos ensued when the nitrogen in Earth's atmosphere turns the exposed Screegit into a giant, acid-spitting monster with Ben having to keep it from wrecking the city.
Current Alien Debuts: Ampfibian, Swampfire, Wildmutt, JuryRigg, Grey Matter, Nanomech It Was Them
Dr. Animo has escaped his Plumber prison, and Ben and Rook must track him down before he turns the world into his personal mutant ant farm. At the same time, Ben thinks that Dr. Animo has been sending Khyber's Pet Dog after him.
Current Alien Debuts: Crashhopper (official debut), Rath, Echo Echo, Diamondhead (16 Year Old Ben).
Nemetrix Alien Debuts: Slamworm, Mucilator (Predator to Crashhopper).
Note: This episode will air in Australia on October 21 2012. This episode aired in Latin America on October 22, 2012. So Long, And Thanks For The Smoothies?
When Ben and Rook investigate a mysterious alien ghost ship, they discover that Argit, the Vreedle Brothers, and the Incursions are all fighting for possession of an universal doomsday device dubbed The Anihilaarg .
Current Alien Debuts: Alien X
Note: This episode aired in Australia on October 14, 2012. This episode aired in Canada on October 6, 2012. This episode aired in Latin America (including Brazil) on October 15, 2012.
Note 2: Ben successfully uses Alien X by recreating the universe due to the catastrophic device that disintegrated it named The Anihilaarg. Hot Stretch
Ben and Rook come across elastic hot-blooded aliens called the Kraaho who plan to activate a volcano with a nuclear bomb engine.
Current Alien Debuts: Eatle, XLR8 (16 Year Old Ben), Articguana, NRG's True Form. Of Predators and Prey Part 1
As a flashback to the episode "The More Things Change" (Part 1), it is revealed that during a fight with Eleven-Year Old Ben Tennyson, Malware touched the Omnitrix symbol on Four Arms. After the battle, he went to Dr. Psychobos and made him create a prototype Omnitrix, the Nemetrix. Back in the present, after a heated argument, Ben and Rook go their separate ways, giving Khyber his best chance to capture Ben. After a long battle, Ben is forcibly changed back into his human form and falls unconscious. A victorious Khyber intends to take Ben to his employer.
Current Alien Debuts Stinkfly (16 Year Old Ben), Ball Weevil.
Nemetrix Alien Debuts Terroranchula (Predator to Ball Weevil) Of Predators and Prey Part 2
While trapped in Khyber's ship Khyber's tells Ben that he needs different alien DNA to complete the evil incomplete version the Nemetrix he also reveals that Dr.Psychobos assigned him to hunt down various species for DNA to transfer it to the Nemetrix and also tells Ben that the reason Dr.Psychobos is creating an evil Omnitrix is because much to Ben's horror ,Malware.After Ben breaks free a brawl breaks out leaving Khyber the victor just when it seems Ben is finished Rook breaks in and saves Ben the duo then reveals to Khyber that they orchestrated the whole "fight" at Undertown and Ben only let Khyber capture him so he can lead them to his ship after a long fight Ben and Rook accidentally crash Khyber's ship eliminating the DNA to complete the Nemetrix making Dr.Psychobos and Malware furious. Current Alien Debuts Humungosaur (Omniverse Debut), Big Chill (Omniverse Debut)