Summary: 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.

Summary: 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.

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

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

Summary: 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.

Summary: 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.

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

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

Summary: 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.

Summary: 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.

Summary: The Omnitrix begins to malfunction and goes haywire when Psychobos steals a piece of an Omnitrix core causing Rook to mutate into a half-Gourmand and a half-Revonnahgander after Ben 10 attempts to complete a transformation.

Summary: 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.

Summary: Magister Patelliday is kidnapped by pirates who rob ships and put them in giant glass bottles to sell them. They intend to devour Patelliday. Any attempts at rescue are hard, since they have a Krakken and a robot army.

Summary: Ben and Rook must stop Trumbipulor from gaining absolute power while Blukic and Driba set out to find Mr. Smoothy's.

Summary: Ben and Rook are attacked by Khyber at a festival.

Summary: Billy Billions turns Ben and Rook into kids again.

Summary: Ben and Rook visit Rook's family while Revohnnah is attacked by an old foe.

Summary: When Eon forces young Ben and teenage Ben to switch minds, only the time-traveling Professor Paradox can sort things out and help Ben stop Eon from taking over the timelines.

Summary: Ben meets an alternate version of himself while searching for a 23rd Mr. Smoothy's store.

Summary: As payment for destroying his car, Mr. Baumann orders Ben to make deliveries for him without using the Omnitrix.

Summary: Dr.Psychobos and Khyber infiltrates Galvan Prime on the orders of Malware.

Summary: Ben must deal with a past failure; a deranged Malware launches his final attack.

Summary: The Gourmand queen is captured, forcing Ben and Rook to rally her feuding subjects to save her.

Summary: Ben and Rook have to escort Vilgax to a maximum-security prison planet, and defend Earth against the Incursean armada.