the prometheus is traveling back to earth with a hyperspace engine from an al'kesh. every couple of hours, the prometheus has to jump out of hyperspace to cool down the al'kesh hyperspace engine. the prometheus comes near a nebula that samantha carter thinks doesn't conform to nebulae she has previously studied. when they jump out of hyperspace, the prometheus is attacked by an unknown vessel. they can't jump into hyperspace because the engines need to cool down. the prometheus is chased into a gas cloud by the alien ship. samantha carter is knocked out when she tries to convert power from auxiliary to the hyperspace engine to make a small hyperspace jump into the cloud. when she wakes up, all the crew members other than her have disappeared. she alone must get herself and them to safety. she has visions of a little girl running around the ship, playing with bubbles and of her friends, who vocalize her worries and theories about her predicament. teal'c at one point grabs carter by the arm and warns her that if she falls asleep she will die.