Ben 10: Alien Force, The Secret of Chromastone

In the middle of fighting a Techadon robot, Ben, Kevin and Gwen are unexpectedly transported by the Omnitrix to an alien planet named Primus.

Gwen travels back in time to prevent the accident that turned Kevin into a monster from ever happening. But she ends up altering history forever.

Ben meets up with Tetrax, but is caught off guard when Tetrax demands that he give him Chromastone. Before Ben has a chance to explain, Tetrax attacks.

The Plumber's Helpers are called upon by Grandpa Max to rescue him from an abandoned space station where he is being attacked by -- Ben!

Kevin finds his house ransacked and enlists Ben and Gwen's help to find out who did it and why. They soon cross paths with a deadly criminal.

Albedo Ben has stolen the Ultimatrix from Azmuth and has used it to kidnap Gwen and Kevin. So Ben goes to face Albedo Ben and rescue his friends.

A defeated Ben gives up the Omnitrix to save himself and his friends. Powerless, he boards Vilgax's ship for their final battle!