Complete story — includes the ending
A pair of rogue half-human Plumbers' kids, a female human-Kineceleran named Helen Wheels, and a male human-Tetramand named Manny Armstrong, have been attacking stray DNAliens and all other aliens they can find, and sucking them into a Null Void projector, believing it to have vaporized them. Believing that the team is DNAliens in disguise, they kidnap Kevin, intending to use him as bait for Gwen and Ben. After his rescue, the two sides work things out. After looking at a database of the aliens they captured and put into the Null Void, Ben realizes that some of them may have been Plumbers' kids. To make things right, the duo set out into the Null Void to rescue those they wrongfully imprisoned.
Sources and content license
Source and revision history · Adapted from Wikipedia contributors, List of Ben 10: Alien Force episodes. HTML formatting and reference markers removed. · Content license