Sisko encounters Michael Eddington, his former Starfleet Security Chief, who betrayed him and joined the Maquis. Obsessed with capturing the traitor, Sisko pursues him in the U.S.S. Defiant. When Sisko gives the order to fire, the ship experiences a massive computer failure — caused by Eddington. Returning to Deep Space Nine in the disabled Defiant, Sisko learns that the starship U.S.S. Malinche has been assigned to apprehend Eddington. Angry and humiliated, Sisko risks everything and takes his damaged ship back into space to find his former crew member.

Kenneth Marshall (Michael Eddington)
Eric Pierpoint (Captain Sanders)
Aron Eisenberg (Nog)

• The new "holocommunicator" debuts in this episode.
  
• Eddington fires a biogenic weapon on a Cardassian colony.