When The Changeling begins, the viewer is taken on a whirlwind tour of a busy, big-city hospital, with doctors, nurses and other assorted staff rushing around, until we focus on an operating room. A restrained Teal’c lies on the table, with none other than the deceased Apophis himself looming nearby, maliciously getting ready to perform the operation. Teal’c abruptly awakens with a start in a bunk, one of many in a communal sleeping quarters. When he gets up, another man--who turns out to be Jonas--notices that there’s something wrong. He gets up and checks with Teal’c, making sure he’s all right. Teal’c assures the probie firefighter that he’s fine; he figures that it was just a bad dream, probably due to stress brought on by the upcoming operation, where he’s planning on donating a kidney to Brea, his close friend and mentor.

The following day, Teal’c’s fire company, under the command of Fire Chief Jack O’Neill, responds to a car crash on a bridge. Fire Captain Samantha Carter barks orders at Jonas and the other probies as they fight a steadily losing battle to try and save one of the drivers, who’s trapped in a car that’s about to explode. When Teal’c sees that the trapped man is Brea, he disregards his own safety and races towards the car to try and save him--yet the car explodes, throwing him back several feet. Miraculously, Teal’c only suffers a mild headache. Yet he keeps having strange nightmares, along with hallucinations, that concern O’Neill enough to ask a psychologist friend of his to pay Teal’c a visit: Dr. Daniel Jackson.

The Changeling was written by actor Christopher Judge, who plays Teal’c, and it’s an extremely well-written story, with plenty of bizarre twists and turns worthy of an episode of the Twilight Zone. And the whole thing still makes sense once it gets wrapped up at the end. In director Martin Wood’s capable hands, the episode is also very taunt and gripping, and the firefighter scenes are wisely treated with the same amount of gravitas as the Stargate sequences. This episode was very inspired; watching the Stargate characters in a completely different light as firefighters is a lot of fun. And yet having Teal’c, O’Neill, Sam and Jonas as firefighters is also a valid metaphor for their real jobs at the SGC, which is to put out "fires" all over the galaxy while helping as many people as they can.