Ben 10: Ultimate Alien - Prisoner #775 is Missing

Seizoen: 2 - Aflevering: 12 / 32 - Eerst uitgezonden: 29 april 2011 - Episode ID: 596709

The secrets of Area 51 are revealed to Ben Tennyson by Colonel Rosum after Old George infiltrates Area 51. (ChamAilen and Ultimate Wildmutt first appears in this episode).