The Klingons begin an invasion of Cardassia in an attempt to secure a foothold near the Wormhole and a forward base against a possible invasion by The Dominion. When the Klingons end its peace treaty with the Federation, Sisko must help Klingon Starfleet officer Worf decide where his loyalties lie.

Avery Brooks (Captain Benjamin Sisko)
Rene Auberjonois (Odo)
Michael Dorn (Lt. Commander Worf)
Terry Farrell (Lt. Cmdr. Jadzia Dax)
Cirroc Lofton (Jake Sisko)
Colm Meaney (Chief Operations Officer Miles O'Brien)
Armin Shimerman (Quark)
Alexander Siddig (Dr. Julian Bashir)
Nana Visitor (Major Kira Nerys)

Andrew Robinson (Elim Garak)
Penny Johnson (Kassidy Yates)
Mark Alaimo (Gul Dukat)
Robert O'Reilly (Chancellor Gowron)
J.G. Hertzler (General Martok)
Obi Ndefo (Drex)
Christopher Darga (Commander Kaybok)
William Dennis Hunt (Huraga)
Patricia Tallman (Weapons Officer)
Judi Durand (Station Computer Voice)

• This episode was the two-hour Season 4 premiere.
  
• The Khitomer Accords is the peace treaty signed between the Federation the Klingon Empire.
  
• The Cardassian Central Command was overthrown and the government taken over by civilians. The new civilian government is the Deteppa Council. Gul Dukat is Chief Military Advisor. The Klingons believe that this uprising was engineered by the Dominion.
  
• The Deep Space Nine Title Theme has been "jazzed up" a little with an underlying beat. The opening credits also were revised to show the Defiant and other ships docking at DS9, ending with the Defiant entering the wormhole.
  
• Also during the opening credits, Siddig El Fadil has changed his stage name to Alexander Siddig, and Michael Dorn (Lt. Commander Worf) joins the DS9 cast.
  
• Dax has been promoted to Lt. Commander. Bashir was promoted to Lieutenant (from Lt. Junior Grade).
  
• Worf is made Strategic Operations Officer, transferring to command division (with a uniform change from gold TNG style to red DS9 style).
  
• Captain Sisko has shaved his head and kept his goatee.
  
• General Martok is the captain of the IKC Nagvar, the new flagship of the Klingon fleet. General Martok had Commander Kaybok killed for failing to follow orders to search the Zoza, Kassidy Yates' ship.
  
• Worf's brother Kurn now has a seat on the Klingon High Council.