Ben hopes to vanquish Aggregor for good but there are complications not least of which includes Ben falling into a time barrier. He is rescued by Gwen but Ben's 10-year-old self comes out with him! Meanwhile a mysterious alien girl named Eunice appears; she has no recollection of what happened before her crash landing but she is being hunted by a common enemy.
Ben 10 Ultimate Alien: Collection 2
We're In For Some Not So Pleasant Surprises