The Gamekeeper (S02E04)

Col. Jack O'Neill and the SG-1 team travel to P7J-989, where they discover a beautiful garden and a dome full of strange metallic chambers. Inside each podlike chamber is an unconscious person. As the team inspects the chambers, they are trapped and knocked unconscious. They awaken to find that they are reliving pivotal moments in their lives, in the hope of changing the outcome: Teal'c joins O'Neill on a battlefield where the colonel lost a patrol, and witnesses the death of his parents in a freak accident. A shadowy figure called The Keeper steps out of the illusion and explains; they are part of a game that feeds memories into a virtual reality he has created for the amusement and edification of his "residents" in the metallic chambers. His guests are here, he says, because the planet has been rendered uninhabitable by pollution. Soon enough, the team discovers that he's lying, and when they threaten to reveal his deceit to his residents, he admits defeat. ... Or does he? (Metro-Goldwyn-Mayer (MGM))