After parting ways with Gwen and Kevin, Ben is assigned a new alien partner named Rook Blanko. Meanwhile, Khyber the Hunstman targets Ben as his next prey.

Rook and Ben find a mysterious alien city under Bellwood after stopping 3 alien crooks: Liam, Fistina, and Bubble Helmet from blowing up Mr. Baumann's superstore in a protection racket.

The Megawhatts that Ben fought in his youth seek his help when they are being used as a power source for the villain Fistrick.

Infiltrating the Plumbers' base, Khyber uploads footage of young Ben's encounter with a corrupted Mechomorph named Malware.

Ben and Rook must stop a giant rampaging alien from destroying Bellwood while dealing with a peace-loving alien-rights activist who doesn't want it hurt.

Ben and Rook attempt to stop Dr Animo and his giant ants.

When Ben and Rook investigate a mysterious alien ghost ship, they discover that Argit and the Vreedle Brothers are fighting for possession of a doomsday device.

Ben and Rook come across elastic, hot blooded aliens that plan to activate a volcano with a nuclear bomb engine.

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.

While trapped in Khyber's ship, Khyber tells Ben that he needs different alien DNA to complete the evil incomplete version of the Omnitrix the Nemetrix. He also reveals that Dr.Psychobos assigned him to hunt down various species for DNA to transfer it to the Nemetrix.

11-year-old Ben, Gwen, and friends go on the adventure of a lifetime in their own backyard.

Khyber, aided by a booger-like Slimebiote named Skurd, attacks Ben & co, but the tables turn when Skurd gloms onto Ben!

Ben, Skurd, and Rook find themselves caught in an endless time loop as enemies from the future converge on Bellwood.

Ben and Rook join Kai Green on a perilous alien relic hunt through South America.

Charmcaster traps Gwendolyn in Ledgerdomain to exact her revenge once and for all.

While Rook is stuck on graveyard shift at Plumber HQ, his sensei Kundo returns as a cyborg to purge the galaxy of technological influence.

Ben finally manages to rid himself of Skurd... just when he needs the Slime-Biot most.

Ben fights for his wife on an alien reality show.

The Time War races towards its dramatic conclusion, with the fate of the entire universe and everything in it since the very beginning of time resting in the hands of Ben 10!

Ben and Rook follow Maltruant through the time stream. Ben has an adventure with George Washington, in 1773, fighting Maltruant and Vilgax. After defeating Vilgax, Ben and Rook chase Maltruant in the time stream to the beginning of time itself onto the starship of the Contemelia (the creators of the Annihilaarg) where Maltruant attempts to create a universe of his own using his own Anihilaarg. In a climactic battle, at the beginning of time Ben nearly dies trying to stop Maltruant from building his own universe but then it is revealed that the Omnitrix has a fail-safe to prevent its keeper from dying.