When 10-year-old Ben Tennyson finds a mysterious device, he's able to turn into a variety of alien heroes, each with uniquely awesome powers.
With such abilities at his disposal, Ben realizes a greater responsibility to help others and stop evildoers, but that doesn't mean he's above a little superpowered mischief now and then.
Ben 10 is just your average story about an ordinary kid, a strange watch and super alien heroes.
Five years after the events chronicled in the original Ben 10 series, 15-year-old Ben Tennyson chooses to once again strap on the awesome Omnitrix, an alien wristwatch that gives him the ability to transform into any one of ten different alien species while gaining their bizarre super powers in the process. Joined by his energy-controlling cousin Gwen Tennyson and his matter-absorbing former nemesis Kevin Levin, the three must work together to gather and train a team of other teenaged heroes for the upcoming apocalyptic battle.
Picking up a few weeks after where Ben 10: Alien Force leaves off, Ben 10: Ultimate Alien follows the now sixteen-year-old Ben. The Omnitrix has been destroyed and Ben must learn to master the secrets of the new Ultimatrix, a gauntlet-like version of the old Omnitrix that not only gives him access to his original powers, but also allows him to evolve his alien forms into even stronger versions (called "ultimate" forms).
In the pilot, a young fan named Jimmy Jones deduces Ben's secret identity and reveals it to the world. Ben becomes an overnight celebrity, hailed by kids as a hero but distrusted by adults as a possible threat. With Gwen, Kevin and Grandpa Max still at his side, Ben continues to battle alien threats to the galaxy including finding five aliens that were attacked by a villain named Agreggor.