Complete story — includes the ending
While Ben obsesses over fulfilling Max's request to find other Plumbers' kids, Gwen and Kevin come at odds over their mutual romantic feelings and Kevin's inaction in asking her out. The team encounters a weakened high school girl named Trina who nearly causes a car accident, which is averted by a superpowered boy named Michael Morningstar, who reveals himself as another Plumber's kid. Michael explains that something is causing girls at his school to become zombified monsters, and they agree to investigate together.
They find and battle a group of zombie girls, who escape after Michael causes debris to fall between them. Gwen, infatuated with Michael and annoyed with Kevin, agrees to go on a date with him. Kevin, distrusting Michael, convinces Ben to check on her with him, where they find Michael absorbing her powers and turning her into a zombie. Michael is revealed to have been the one zombifying his classmates, stealing their life force for themselves. Gwen is able to defeat Michael, and the girls take their life force back from him, deforming him in the process. Kevin then destroys Michael's Plumber's badge, and Ben apologizes for being too quick to trust Michael. Omnitrix alien debuts: Chromastone
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