Ben 10 centers around Ben Tennyson (Tara Strong), a ten-year-old boy on a cross-country summer vacation, with his cousin Gwen (Meagan Smith) and their grandfather Max (Paul Eiding). On their first night camping in their grandfather's RV affectionately named the "Rust Bucket," Ben finds an alien pod with a mysterious watch-like device named the Omnitrix. The device then permanently attaches itself to his wrist giving him the ability to transform into a variety of alien life-forms each with its own unique skills and powers. With his new found super powers Ben has to learn the responsibilities of being a hero.
During their vacation, the Tennysons are attacked by various of enemies ranging from space aliens to supernatural entities. One of the most feared archenemies is Vilgax (Steven Blum) a relentlessness intergalactic conqueror who wants the Omnitrix to create a shape-shifting army to take over the galaxy. There are many other villains including Kevin Levin, Charmcaster, Dr Animo, Zs'skayr and The Forever Knights.