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

When Ben and Gwen learn that their grandmother Verdona is an alien being, Verdona insists that Gwen should come along with her to her home planet and improve her abilities. With this, Gwen is faced with a difficult decision between a human and alien life.

An alien emperor plans to destroy the planet Earth for kidnapping his daughter. In order to save the planet, Ben must uncover the secrets of Alien X.

Ben and the gang rescue a runaway prisoner of the DNAliens.