While on a seemingly endless summer vacation with his Grandpa Max and Cousin Gwen, Ben Tennyson discovers an alien watch, the Omnitrix. This amazing device gives Ben the ability to transform into any one of ten spectacular and powerful aliens. Ben, Gwen and Max travel the country in their motor home, affectionately known as the Rust Bucket, seeing the sights, stumbling into adventures, and beating down would-be villains while generally having a blast.