While returning to the station, the crew of the Defiant come upon the aftermath of a Jem'Hadar attack on Deep Space Nine. Destroying one of the upper pylons and leaving many dead and wounded in their wake, the Jem'Hadar have mysteriously taken several electronic items. Captain Sisko and his crew head into the Gamma Quadrant with the Defiant in order to trace the attackers by their ion trail.
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.