“Emissary: Part 2” is the second part, or second episode, of the feature length – or two part – first episode of season one of Star Trek: Deep Space Nine.
In the previous episode, “Emissary: Part 1”, Commander Sisko had been given an Orb by the Bajoran religious leader. Lieutenant Dax had tracked the evidence, and found that there was an area of space that seemed significant, so she and Sisko took a runabout to investigate it – after first disabling the visiting Cardassian ship’s sensors.
What is at the point is a stable wormhole – the first of its kind – connecting the Alpha Quadrant with the Gamma Quadrant of the galaxy, 70,000 light years away.
The Cardassian Gul Dukat’s ship decides to follow, and Dax is returned, and the wormhole shuts – because it’s inhabited by an alien species.
With a Cardassian ship missing, more arrive, and the station is in serious peril, for it is practically unarmed and the Enterprise has left. Sisko needs to come to some sort of agreement with the wormhole aliens.