“‘Til Death Do Us Part” is episode eighteen of season seven of Star Trek: Deep Space Nine.
In the previous episode, “Penumbra”, Ezri and Worf had got together – which could be seen coming, even though joined Trill are not supposed to have relationships of that type with people the prior host had relationships with – after she rescued him and they wound up crashed on a planet without communication. They were then captured by the Breen. Sisko had also proposed to Kassidy and she had accepted. Then Sisko got a vision from one of the wormhole aliens, the one who had inhabited his mother, Sarah, who told him that he shouldn’t marry Kassidy, as Kassidy could not walk Sisko’s path with him, and attempting to do so would bring him sorrow. On Cardassia Prime, Gul Dukat had himself surgically altered to look like a Bajoran.
Sisko hasn’t told Kassidy yet, but he has told Jake. Sisko also hasn’t exactly decided what he wants to do yet. Then Kai Winn arrives; she has come to assist with the Emissary’s wedding and wants to perform it. Sisko mentions to the Kai that he has had a vision from the Prophets about a trial, but doesn’t repeat what they said about Kassidy. Kai Winn has never had a vision sent from the Prophets, which clearly bugs her. Then, immediately after seeing Sisko, she has one. A vision in which the Prophets say that the Sisko has faltered and that she will be sent a guide to bring about the Restoration. Typically for the Prophets, the vision is vague, yet unhelpful, but something seems to be… off with how they behave.
Worf and Ezri are still on the Breen ship heading somewhere. The Breen seem to want something and Worf says that they are dangerous. No-one has ever seen a Breen without its helmet either, so their actual appearance is unknown.
On Cardassia Prime, Weyoun wakes up Damar and says that they are leaving. Damar has matters to deal with first, namely Dukat. Which Weyoun does know about.
Dukat himself arrives on DS9 of course and, not exactly surprisingly, goes to see Kai Winn. Where he appears to match up with what the Prophets told her in her vision. Which, given that they are a little off, suggests that what the Kai saw were actually Pah-wraiths, Pah-wraiths using Kai Winn’s arrogance and self-importance against her. Which does not bode well.
Sisko tells Kassidy about the vision, and she definitely isn’t happy when he breaks off the engagement. Sisko isn’t happy about it himself either, and may well change his mind, despite the warning from the Prophets.
Weyoun, Damar and a Founder are heading off in a Jem’Hadar warship, and the Breen are in flight as well. This may not be a coincidence.
There are still many plot threads unresolved and the story continues in the next episode, “Strange Bedfellows”.