After informing Starfleet of Odo's concerns about Gowron being a changeling, Sisko, O'Brien and Odo disguise themselves as Klingons, and accompanied by Worf journey to a fortress deep in the heart of the Klingon Empire. Assisted by Gul Dukat, whose captured Bird of Prey makes a useful transport, they seek to pose as valiant warriors due to be honored by Gowron long enough to trigger an experimental device that will expose the changeling.

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)

Robert O'Reilly (Chancellor Gowron)
J.G. Hertzler (General Martok)
Mark Alaimo (Gul Dukat)
Casey Biggs (Glinn Damar)
Robert Budsaka (Burly Klingon)
Tony Epper (Drunken Klingon)
John L. Bennett (Towering Klingon)
Ivor Bartels (Young Klingon)
Robert Zachar (Head Guard)

• General Martok was the changeling. The changelings tried to trick Odo into killing Gowron to start a war between the Klingons and the Federation. Worf and Garak find the real Martok later this year in the episode "In Purgatory's Shadow".