Kevin shatters Ben and Gwen's trust when he steals the Rust Bucket to sell for alien technology on the black market.

Ben, Gwen and Kevin discover that Vulkanus is planning to drill the center of the Earth and drop a bomb into the hole. Destroying the planet.

Ben, Kevin and Gwen come across an alien box that can forms into a robotic version of whatever it sees. It power becomes a liability when the Vreedle brothers decide to take the box for themselves.

Zaw-Veenull asks Ben to deliver Prince Tiffin to Jarret in order to keep peace between the two species. Shortly, after their trip in space, the Omnitrix malfunctions and turns Ben into an Appoplexian named Rath who wants to fight anything that breathes.

The Plumber's Helpers are called upon by Grandpa Max to rescue him from an abandoned space station where he's being attacked by Ben! The team must now find a way to work together as they try to save Max, stop Ben, and keep the space station from crashing to Earth.

Kevin returns home to find his house ransacked, so he enlists Ben and Gwen's help to find out who did it and why. They soon cross paths with Ragnarok, a deadly criminal who recently broke free from the Null Void and is in search of a special key. Kevin is intent on stopping Ragnarok from obtaining the special key, especially after he learns the truth about Ragnarok and his father.