Crew members are abducted from their beds by unknown aliens.
Commander Riker and several other officers begin to experience strange symptoms, including odd dreams and lost time. They suspect that they have been abducted by aliens, and they try to piece together what happened. Using a holodeck reconstruction, they discover that they have been taken to a laboratory where unknown beings carried out experiments.
The story is a science-fiction horror, with a distinct tone of dread. It is inspired by tales of alien abduction, and it is one of the scariest episodes of the series. The crew has to find the portal to the aliens' dimension before they strike again. The suspense is carefully built and the episode is a favorite with fans who like the unnerving side of the show.