Stardate 50814.2: After finishing up a long survey mission in the Gamma Quadrant, the tired crew of the Defiant heads back towards the wormhole. On their way, Jadzia Dax spots a planet with an unusual barrier around it. With the science officer confident that taking a look a the planet would not cause any problems, the Defiant passes through the planet's atmosphere. The barrier causes damage to the ship and they have to land to make repairs. As they look around for a place to set down, they are hailed by the inhabitants of the planet, who are the great-grandchildren of the Defiant's crew. The barrier created a temporal distortion, sending them back to the past by two centuries.
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.