Stardate 47603.3: While investigating an unusual particle field in the Gamma Quadrant, Lieutenant Dax and Odo come across rare omicron particles on a planet. Beaming down to the surface, they are swept up in a village's investigation to find out what happened to twenty-two of their fellow inhabitants. Back on Deep Space Nine, Kira, covering for Odo while he's away, welcomes Vedek Bareil to the station, and Commander Sisko assigns Chief O'Brien to work with his son so that Jake can prepare himself for the day he enters Starfleet Academy.
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.