Goodbye and Good Riddance is the fifty-second and final episode of Ben 10. It is a "what if" episode.
Ben returns home after summer vacation ends and Max tells him that he must keep the Omnitrix a secret.
This is made all the more difficult by Ben's classmates who admire Ben's alien heroes while completely oblivious to Ben being them. Initially disappointed, Ben gets the chance to use the Omnitrix when Vilgax attacks, looking to take the Omnitrix from Ben. All four Tennysons (Ben's father helps) fight off Vilgax's Drones running amok in the city. When Vilgax appears again, easily fending off Ben, Ben's father suggests leading him into the underground gas line, which they ignite to incinerate the villain. Ben's secret is revealed to the public and Gwen ends up transferring to his school. Just when it seems like everything is quiet, Dr. Animo shows up with a mob of mutated animals, which Ben and Gwen get ready to fight.