As the Goa'uld send bombs to splatter against the Stargate's protective iris, the SG-1 team faces several problems close to home. Colonel O'Neill wants to add a new member to the team: Teal'c, the Jaffa who risked his own skin to save O'Neill and his team on the other side of the Stargate. But General Hammond won't approve the appointment and O'Neill must watch as military intelligence agent Colonel Kennedy treats Teal'c like a guinea pig. To make matters worse, Kawalsky, O'Neill's right-hand man, has been having terrible headaches caused by an immature Goa'uld that attached itself to his brain. What they don't realize is that this larvae is trying to take over Kawalsky's body in an attempt to go back through the Stargate. Eventually the goa'uld attempts to leave and the SGC catches on and prepares to operate on Kawalsky to remove the symbiote.
With guidance from Teal'c, the doctors operate to remove the alien, but they don't get it in time - the symbiote transferred its consciousness entirely out of its body and into Kawalsky. Teal'c is being transferred by Kennedy for scientific experimentation but realizes that Kawalsky is trying to escape after setting the base auto-destruct. Teal'c intercepts him and they fight over the active Stargate - Teal'c thrust Kawalsky's head into the gate as they shut down the gate, removing the back of Kawalsky's skull. With Teal'c having proven his loyalty, Hammond has the leverage to override Kennedy and get him appointed to SG1