The team is confronted by a Plumber Magister who accuses them of impersonating Plumbers. Meanwhile, a new foe allies himself with a HighBreed commander.
During battle, Ben and a HighBreed commander are teleported to a distant world. They must put their differences aside if they're going to have any chance of finding a way to return to Earth.
When Gwen demands that Kevin take her to her school's summer dance, Ben offers Kevin good advice. Meanwhile, Ben and Julie contend with a malfunctioning Omnitrix and a rogue Big Chill.
When the team turns to Cooper to get Kevin's transporter device working properly, they find their young friend has been abducted. Finding him leads to a well-hidden DNAlien base.
The Forever Knights develop a ship they will use to travel to the dragon's home world to destroy all dragons. To make it fully functional, they capture Ship, the alien Upgrade pet Ben and Julie met.
Helen of the Plumbers' Helpers calls Gwen, pleading for help, so Ben goes into the Null Void alone to assist her, finding an old enemy with new powers - and other surprises.
Paradox and Azmuth arrive with grave news: The DNAliens are ready to make their move. While Gwen and Kevin gather help, Azmuth reveals some secrets of the Omnitrix and its true purpose.
Though Ben's team fails to stop the DNAlien Fleet from arriving, re-enforcements arrive, but this battle can't be won on Earth. A small group goes to the DNAlien home world to force its leaders to stop the invasion.