"Ben 10: Ultimate Alien" is an animated television series that follows the adventures of a young hero named Ben Tennyson. After acquiring the Omnitrix, a powerful device that allows him to transform into various alien species, Ben faces new challenges as he battles villains and protects Earth. In this series, Ben gains access to the Ultimatrix, an upgraded version of the Omnitrix, which enables him to evolve his alien forms into more powerful versions. Alongside his friends, including Gwen Tennyson and Kevin Levin, Ben learns to harness his abilities while confronting threats from both Earth and outer space.