After accidentally returning to Earth, Crichton discovers it he is in 1985 and he has altered the time line, causing his father to be scheduled to fly on the doomed shuttle Challenger.

Moya takes on a new passenger when Chiana insists that they rescue the young female from the men exploiting her. However, they soon learn that Talikaa is not the innocent that she pretends to be, but rather an alien predator in disguise who plans to feed on their neural energy.