This episode continued the story that was developed during the pilot episode. At the end of that episode, one of the parasites, called the Goa'uld, enters the body of Major Kawalski. Also, one of the servants of the Goa'ulds, Teal'c, betrayed the Goa'uld named Apophis, who Teal'c had worshiped as a god, and came back to Earth with SG-1.
In this episode, the Goa'uld in Kawalski's body starts taking control of his mind. However, since it is not completely mature, it can only take over his body for a short amount of time. After it loses the control over his body, he doesn't remember what happened during that time.
Meanwhile, a General in the military wants to take Teal'c to study him for the valuable information he might give them. Colonel O'Neill doesn't want this to happen, because Teal'c has rights, and just because Teal'c wasn't born on Earth, it doesn't mean that his rights don't exist here on Earth. General Hammond is cautious of Teal'c's loyalty to Earth, but ends up trying to stop the other General from taking him to study him.
This is a very good conclusion to the story set up in the pilot episode. The story is good, and the acting is great. Colonel O'Neill is a friend of Major Kawalski, and at the end, when O'Neill gives the order to disconnect the wormhole, and as a result killing Kawalski, you can tell he is in pain from killing his friend. But then, when Teal'c says that he is sorry that O'Neill had to kill his friend, he says that his friend was already dead. This is a very good follow-up to the pilot episode.