While exploring a jungle planet, Col. Sheppard touches a glowing crystal. Dr. Keller gives him a clean bill of health, but over the next couple of days the rest of the team start sequentially experiencing vivid nightmares, all featuring Sheppard as an antagonist. Things start to escalate when it comes around to Major Lorne, who has a history of sleepwalking and almost shoots Sheppard while asleep. They escalate even further when the team finds Dr. Heightmeyer dead, having been killed in the dream.