Complete story — includes the ending
Vilgax attacks a containment facility near a star imprisoning Zs'Skayr ("Ghostfreak"), demanding that he tell him the secrets of the Omnitrix in exchange for his freedom. Zs'Skayr complies, but betrays Vilgax upon his release, traveling to his homeworld of Vilgaxia and converting the planet's populace into hive mind Ectonurite minions. Vilgax flees to Earth and begs Ben for help, who reluctantly complies. Vilgax leads the team to his home planet, where they enter Vilgax's citadel and confront Zs'Skayr. Ben tricks Zs'Skayr into entering his body and attempts to control him with the Omnitrix, but Zs'Skayr seizes control instead. Vilgax is able to weaken Zs'Skayr long enough for Ben to regain control and revert to his human form, defeating him and freeing Vilgax's people. Ben and his team depart from Vilgaxia, while Vilgax looks on, gloating that he now knows the secrets of the Omnitrix. Omnitrix alien debuts: Ghostfreak
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