When the Enterprise responds to a distress call from the U.S.S. Brattain, they find the Brattain crew dead, except for a catatonic Betazoid science advisor. The Enterprise becomes caught in a Tyken's Rift, where energy is being drained, preventing their escape. The crew begins hallucinating due to dream deprivation, except for Deanna Troi, who experiences a recurring nightmare.

Whoopi Goldberg (Guinan)
Rosalind Chao (Keiko O'Brien)
John Vickery (Andrus Hagen)
Duke Moosekian (Ensign Gillespie)
Craig Hurley (Ensign Peeples)
Brian Tochi (Ensign Kenny Lin)
Lanei Chapman (Ensign Sariel Rager)
Colm Meaney (Lt. Miles O'Brien)
Deborah Taylor (Capt. Chantal R. Zaheva)

• The model for the U.S.S. Brattain NCC-21166 had the name incorrectly spelled as Brittain (it was spelled "Brattain" in the computer displays, the script, and the closed captioning). The model was a modification of the U.S.S. Reliant NCC-1864 from Star Trek: The Wrath of Khan (both were Miranda-class starships).
  
• Deanna's nightmare has a voice telling her "Eyes in the dark...One moon circles." The dream is a telepathic message from a ship trapped on the other side of the rift. The message refers to the binary star system and that they need Hydrogen. Deanna saves the day when she tells the ship trapped on the other side "NOW" in her dream as Data releases Hydrogen. The resulting explosion blows the two ships free.
  
• This episode gives us our first peek at "The Fueding O'Briens" who will make an artform out of arguing on Deep Space Nine.