While in the Great Link ("Broken Link"), Odo suspected that the Changelings were hiding information from him. What he was able to gleen from the Link allowed him to realize that Klingon Chancellor Gowron is actually a Changeling. Starfleet requests that Sisko reveal Gowron for who he truly is and put an end to the hostile actions of the Klingon Empire.
s05e01 - Apocalypse Rising
s05e02 - The Ship
s05e03 - Looking for par'Mach in All the Wrong Places
s05e04 - ... Nor the Battle to the Strong
s05e05 - The Assignment
s05e06 - Trials and Tribble-ations
s05e07 - Let He Who is Without Sin...
s05e08 - Things Past
s05e09 - The Ascent
s05e10 - Rapture
s05e11 - The Darkness and the Light
s05e12 - The Begotten
s05e13 - For the Uniform
s05e14 - In Purgatory's Shadow (1)
s05e15 - By Inferno's Light (2)
s05e16 - Doctor Bashir, I Presume?
s05e17 - A Simple Investigation
s05e18 - Business as Usual
s05e19 - Ties of Blood and Water
s05e20 - Ferengi Love Songs
s05e21 - Soldiers of the Empire
s05e22 - Children of Time
s05e23 - Blaze of Glory
s05e24 - Empok Nor
s05e25 - In the Cards
s05e26 - Call to Arms
When the Cardassian occupation of Bajor ended in 2369, the mining space station Terok Nor was left abandoned, its systems ripped out. By invitation of the Bajoran provisional government, Starfleet stepped in to oversee the rebuilding and day-to-day operations of the newly christened Deep Space Nine.
The years of Starfleet's nonintervention into Cardassian matters, however, had taken its toll on relations with the Bajorans. Consequently, Starfleet's position was a tenuous one; many Bajorans, suspicious and hostile as a result of decades of Cardassian oppression and brutality, did not greet the Federation's presence with open arms. The Federation's assistance is put to the test as DS9 becomes a center of travel and commerce that stretches into the Gamma Quadrant.