The Changeling

The Changeling is the nineteenth episode of the sixth season of Stargate SG-1.

Plot
In a hospital, a doctor visits a patient. The patient is Teal'c and the doctor is Apophis. Teal'c (who has no tattoo or symbiote pouch) wakes up and is asked how he is by Jonas Quinn, whom he calls "probie" (which is short for probationary fireman). They talk in colloquial English about Teal'c's stepfather and suddenly Teal'c again wakes up after a kelno'reem. He visits the canteen, and is talking to Major Carter when the scene changes to the interior of a fire station. He is talking with the other members of SG-1, who are all members of a fire brigade, about a kidney transplant for Teal'c's stepfather, Bra'tac (whom people call "Brae" in the fireman reality).

The alarm rings and the fire brigade responds to a car crash. There they prepare to help the wounded in the car while Teal'c helps another victim outside the car (who again looks like Apophis). One car catches fire and Teal'c sees Bra'tac alive inside the car as the previously established dead driver. He tries to free him when both cars explode. In the canteen at Stargate Command Teal'c faints and is taken to the infirmary. Dr. Fraiser doesn't know what is happening. Teal'c tries to sleep but wakes up in a hospital bed. He talks with O'Neill, who is again the chief of the fire brigade, about what has happened. Outside he meets Brae (Bra'tac) and Teal'c's wife. Brae says that something is wrong because he has no burns from the accident.

Teal'c is at SGC again. O'Neill and Fraiser talk to Teal'c about his situation and he tells them about his dreams. Teal'c is in the hospital again, where he is visited by Dr. Daniel Jackson, the hospital psychologist. They leave the hospital to talk about Brae and the transplant but Teal'c insists he isn't afraid of the operation. Daniel leaves and Teal'c finds himself back at SGC shortly before he and SG-1 leave on a mission through the Stargate. They go through the gate but Teal'c finds himself in a hospital, where he is confronted by Apophis. A nurse calls out to him and he runs away, only to find himself in the gate room again. He calls out that his symbiote is missing and passes out. Teal'c wakes up on another planet full of dead Jaffa, where he and Bra'tac are lying half dead. Teal'c takes Bra'tac's symbiote and implants it in himself.

Teal'c wakes up at home with his wife Shauna and they talk about the transplantation of the kidney and Teal'c's dreams. His wife convinces him that all is OK. Teal'c says that when he is at the SGC, the fireman life feels like a dream, but when he is in the fireman reality, the SGC seems like a dream. Teal'c tries to tell her that what "where he is is a dream" and that "it can't be real". On the next day Teal'c visits Brae who tells him that his body is rejecting the kidney. Teal'c is shocked and outside the hospital he meets Daniel again. They talk about the operation and especially Teal'c's dreams. Daniel tries to find connections between the two dreams but Teal'c can't say what is real. Daniel says that perhaps both worlds aren't real. The scene shifts again to the gate room, where a badly wounded Teal'c is lying on the ramp and then brought in the infirmary. SG-1 then tells General Hammond that a meeting of the rebel Jaffa was an ambush and that Teal'c kept himself and Bra'tac alive for three days by sharing his symbiote between them.

Dr. Fraiser reveals that because they were sharing the symbiote, it is not strong enough to heal either and all three of them are dying. Some time later Jacob Carter arrives and brings a modified version of Tretonin which has been engineered for Jaffa physiology. They then decide to use it because the symbiote is dying.

When Teal'c wakes up later, Daniel appears at his side and they talk about what has happened. Teal'c thanks him but Daniel says it's all because of his strength.