*During a routine medical exam, SG-1 is sedated and left unconscious, Teal'c awakens to find that the base bas been taken over by aliens capable of taking the form of SGC personnel. No one one base can be trusted. Carter escapes to report the foothold situation to Colonel Maybourne, but alien doubles of O'Neill and Daniel catch up with her. Their identities are revealed when Carter discovers the device that enables their physical transformation, and uses its technology against them. Returning to the SGC, she joins the real O'Neill and Major Davis to expose and defeat the retreating aliens. *Source: Back of card