Some of Ben's old enemies attack a school bus. Ben easily defeats them, the grateful cheerleader thank him. It's a start of a perfect day for Ben. Or is it? Duplicates of Grandpa and Gwen show up and tell him he's been captured, he's in a dream world, and the culprits are keeping him there so they can get the Omnitrix. Can Ben distinguish between what is and isn't real?
The Tennyson pick up Cooper, the grandson of a fellow plumber. They hear the Circus Freaks are at Fort Knox and go to stop them. But the Circus Freaks didn't take any gold, and they're not the only ones involved in the caper. When they finally figure out what the real objective is, they find the Negative 10.
The summer finally ends, Ben and Gwen have to go back to their normal lives. Grandpa Max tells Ben to keep the Omnitrix a secret from everyone, even his parents. Ben agrees, but Vilgax arrives and he'll stop at nothing to get the Omnitrix.