As the Goa'ulds splatter against the protective iris installed inside the Stargate, the SG-1 team faces several problems close to home. Colonel Jack O'Neill wants to add a new member to the team: Teal'c, an alien 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 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 alien larvae that has attached itself to his brain. What they haven't discovered is that this larvae is trying to take over Kawalsky's body in an attempt to go back through the Stargate. With guidance from Teal'c, the doctors operate to remove the alien, but did they get it in time? Or is Kawalsky still under alien control, ready to kill when the order comes?