A group of Trill scientists, led by Dr. Lenara Kahn, comes to Deep Space Nine to use the Starship Defiant to conduct wormhole experiments. Lenara is a joined Trill who, while her symbiont was joined to a previous host body, was married to one of Dax's former male hosts, Torias. Dax, believing that she can control any feelings she may still have for her former wife, decides to meet with Lenara. Despite the fact that the penalty for "reassociation" with lovers from past lives is exile from the Trill homeworld and the eventual death of the symbiont when the host dies, the two have dinner together. As their relationship develops, they must decide if they will destroy their future to stay together.

Susanna Thompson (Dr. Lenara Kahn)
Tim Ryan (Dr. Bajel Kahn)
James Noah (Dr. Hunner Pren)
Kenneth Marshall (Lt. Cmdr. Michael Eddington)

• The Trill are trying to create an artificial wormhole. At the dinner party, Sisko wishes them luck on trying to create "the galaxy's first artificial wormhole." DS9 is positioned at the galaxy's first artificial wormhole, which Sisko himself discovered!
  
• Torias Dax was married to Milani Kahn.
  
• This episode featured the infamous Jadzia and Lenara "lesbian" kiss.