Ben, Gwen, and Kevin stow away aboard the ship of their new alien adversaries, and discover that their leader is plotting a campaign to exterminate the human vermin of Earth. Ben also discovers that the Omitrix no longer protects his human form from damage whenever his alien forms are harmed
The gang runs into a Heatblast as they search for other Plumbers who are using Grandpa Max's badge.
Ben steals a robotic glove from Kevin's GTO to battle the bullies, but it causes trouble instead.
A time traveling hero joins forces with the gang to battle a monster ripped straight from the 1950s.
Ben is torn between his mission and the escaped dragon he has captured from the Forever City after learning about both sides of the conflict.
Ben is afraid he has lost control of Omnitrix.
The DNAliens have kidnapped a child genius so he can build them a mystery arch.
Vilgax, whose power has been greatly increased, challenges Ben for a battle with the winner named ruler of earth.
After tampering with the Omnitrix, Ben, Gwen and the now mutated Kevin have to rush to hunt a small handful of transformations that escaped, before they cease to exist.
Ben, Gwen and Kevin discovers Vulkanus plans on drilling down to the core of earth.
Alien Repo men come to take Ship back to his previous owner.
Charmcaster returns and flirts with Kevin in an attempt to steal all of Gwen's powers.
Vilgax returns with a surprise. He needs Ben's help to save his home planet, from Ghostfreak!.
Kevin and Darkstar go after an old artifact that will fix both of their problems, by sealing their respective powers.
Kevin, Gwen and Ben find an alien box that turns into robots.
Ben is asked to deliver Zaw-Veenull, the Luodan ambassador's, crown price Tiffin to Jarrett. However, when the Omnitrix malfunctions, Ben is turned into an Appoplexian named Rath.
While fighting a Techadon robot, Ben, Gwen, and Kevin find themselves transported by the Omnitrix to a planet named Primus. They find out that they are not alone on the planet and Vilgax is there trying to stop the Omnitrix.
Despite being warned, Gwen travels back in time in order to prevent an accident that turned Kevin into a monster. When she returns to the present, Gwen finds that her travel in time caused a ripple of events that led to Hex ruling the world. Now, she must fix the damage she created.
Tetrax visits Ben while he is sick, but shocks Ben when demands a Chromastone from him. Ben's situation gets worse when Vilgax shows up and is after the same thing.
The Plumbers' Helpers have to save Grampa Max-- from Ben??
Kevin comes home to find that someone has broken in, and has Ben and Gwen work with him to find out who did it and why. They end up crossing paths with Ragnarok who is looking for a special key, which makes Kevin set out to stop him from getting the key.
Paradox and Asmuth tell Ben that Albedo(from Good Copy, Bad Copy) has stolen the Ultimatrix, as well as kidnapped Gwen and Kevin. Ben has to hurry to save them and stop him and Vilgax.
Ben goes on to Vilgax's ship and tries to stop the invasion of Earth. Ultimately, Azmuth gives Ben the Ultimatrix.