“Rapture” is episode ten of season five of Star Trek: Deep Space Nine.
There are several different story threads in this episode. It opens with Major Kira and Sisko examining a Bajoran artefact that has just been returned by the Cardassians. It’s a very small painting of the city of B’hala. The painting was done 20,000 years ago, and is the only known proof that the city ever existed. There’s a spire in the painting, a Bantaca spire, whose markings would give the exact location of the city, but only the markings on one side can be seen; the other two sides are missing.
Sisko manages to see the reflections of the other two sides in a waterfall, after scanning the painting, and tries to decipher them. There’s an accident in the holosuite, and Sisko becomes obsessed with interpreting them. He also starts getting visions, of both the past and the future, although they aren’t always easy to understand. Bajorans have been looking for B’hala for 10,000 years – Sisko finds it in days, but his visions don’t stop.
Bajor has also been granted permission to join the Federation, and various bigwigs are heading to DS9, including Kai Winn. Kasidy Yates returns as well, after spending six months in prison after the events of “For the Cause”. Sisko is a bit uncertain about seeing her again, but his attitude seems to change after the visions start.
Finding the city of B’hala reinforces Sisko’s status as the Emissary – even with Kai Winn, never his biggest fan. He is desperate to continue getting the visions, but they are killing him.