Ben discovers that the Forever Knights are trading weapons with the DNAliens, while at the same time, Grandpa Max has mysteriously gone missing. He decides to return the Omnitrix on his wrist and go hero once again.

Ben, Gwen, and Kevin follow a lead that takes them to a secret base in the desert. There they hope to find Grandpa Max but instead find a Highbreed spaceship with a giant cannon.

Gwen discovers that Grandpa Max's badge is able to signal other Plumbers. However, by using it, they meet up with a familiar face, a pyronite.

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.

Cooper is kidnapped by the DNAliens, who want him to build a mystery arch.

To find and destroy the alien dragon species, the Forever Knights capture Ship to control a starship they built out of alien technology to locate their homeworld and destroy them.

When Ben's parents discover his ability to turn into aliens, they forbid him from using the Omnitrix and later ground him from using it again. Eventually Gwen is grounded too leaving Kevin to stop the DNAliens.

Ben, Gwen and Kevin gather their allies to counter the threat of the incoming Highbreed fleet. Azmuth reveals a secret about the Omnitrix.

Ben goes to the HighBreeds' world in an attempt to stop their attack on Earth.