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.

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

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

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.

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.

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.

Professor Paradox unites the good Bens from across all dimensions to take on Vilgax, Eon, and the evil Bens in the ultimate showdown.

Ben gets dragged into intergalactic court by the other Celestialsapiens for recreating the universe.

Kevin and Argit attempt to warn the Amalgam kids about the Rooters intentions. Meanwhile, Ben, Rook, and Gwen set off to find Kevin and land themselves in the Null Void.

The Rooters have seemingly turned Kevin and the Amalgam kids against Ben. Can Rook and Gwen help him overcome the opposition and escape the Null Void?

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

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

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.

Gwen and Kevin visit Bellwood. Kevin tells Ben that he must hide himself from The Tetramand Princess Looma as she is hunting him as Looma wishes to marry Kevin.

Billy Billions turns Ben and Rook into kids again.

Ben must deal with a past failure while a deranged Malware launches his final attack on Azmuth.

Ben and Rook must stop Zombozo and the Circus Freaks from turning everyone in Bellwood into zombie clowns!

An old enemy emerges while Ben and Rook visit Kevin and Gwen at college.

Vilgax's former lackey Psyphon is elated when his master returns.

Ben and Rook are called to London to investigate the Forever Knights' latest activities.

Dr. Animo from the future comes back to the present to help himself defeat Ben once and for all.

Vilgax and Eon team up to wipe out every Ben in every dimension.

Billy Billions, Kangaroo Kommando, and Captain Nemesis team up to take down Ben, and claim his place as protector of Bellwood?!?

Psyphon and a gang of bounty hunters are after Argit, who is in possession of a dangerous weapon.