 Upon returning to the SGC from there first mission, SG-1 learns that Major Kawalsky, O Neill s right-hand man, has become infected by a Goa uld during their mission. As the SGC s doctors look for a way to remove the Goa uld, Colonel Kennedy interrogates Teal s, who O Neill wants to join SG-1. As time goes on and Kawalksy s mind is taken over more and more by the Goa uld, doctors preform emergency surgery in a desperate attempt to save Kawlasky. But they prove to be too late as Kawlasky escapes and activates the base s self-destruct, leaving only Teal c to stop him.