Menace

Menace is the nineteenth episode of the fifth season of Stargate SG-1.

Plot
SG-1 arrives on a world ravaged by war. In a building, they find a young woman gynoid, completely unscathed. Carter and Daniel convince General Hammond to allow them to bring the gynoid back to the SGC for further study. The android is activated and speaks with SG-1, telling them its name is Reese, but will not reveal any details of how her world was destroyed when asked.

O'Neill, Teal'c and SG-8 return to the planet and discover Replicator blocks, they realise that the world was annihilated by Replicators. After the team's return Reese creates a Replicator as a toy for her and Daniel Jackson to play with. He is shocked, and the Replicator is contained, being placed in a reinforced glass box guarded by Teal'c, much to Reese's dismay. Reese becomes upset, believing everyone hates her because she was 'Created Wrong', and believes that they all wish to destroy her and her toys, the Replicators. Daniel tries to console her and convince her otherwise, in the process learning that the people of her world came to fear her and her toys, leading them to attempt to destroy them. Reese admits that she told her toys to 'make more of themselves' and that she 'taught them how to defend themselves', then lost control of them, accidentally creating the Replicator plague.

Eventually, Reese, believing that everybody is plotting to destroy her and her toys, again, creates an army of Replicators and attempts to escape through the Stargate, locking herself in the gate room while she learns how to use the Stargate. Fearing that she will lose control of her Replicators again, General Hammond decides that they must shut down or destroy Reese. Daniel attempts to shut her down by tricking her into trusting him again and then removing her power source, while Carter and General Hammond activate the base's self destruct and Teal'c, O'Neill and several SGC personnel attempt to break into the gate room. Daniel fails but continues trying to convince Reese to stop what she is doing while the self destruct is activated and the gate room blast doors are cut open. After activating the Self Destruct, Carter realizes that the Replicators are beginning to act independently of Reese, as they had feared. O'Neill breaks into the gate room, just as Daniel appears to have convinced Reese to deactivate the Replicators. O'Neill shoots Reese, inflicting mortal damage on the gynoid. As Reese shuts down, the Replicator blocks separate. Even though he understands that O'Neill had no choice, Daniel becomes extremely angry at him, since he believed he had convinced Reese to stop the replicators, that she turned them off rather than because O'Neill destroyed her and that he destroyed their only chance to stop the Replicators.