Stardate 46531.2: Upon returning from the Gamma Quadrant, the Ganges, with Dax and a subordinate on board, suffers total power failure. The Runabout makes it to one of the docking ports, and Commander Sisko and Major Kira try to open it to no avail. Before Chief O'Brien supplies an external power coupling to the Runabout, Dr. Bashir's tricorder identifies an extra passenger aboard the Ganges. Once the door is open, the crew finds that the passenger is Vash, the close friend of Enterprise Captain Jean-Luc Picard, who had not been seen since she went on a tour of the Universe with Q.
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.