'Til Death Do Us Part (Star Trek: Deep Space Nine)

"'Til Death Do Us Part" is the 168th episode of the television series Star Trek: Deep Space Nine. This episode first aired the week of April 12, 1999 on syndicated television.

Set in the 24th century, the series follows the adventures of the crew of the Starfleet-managed space station Deep Space Nine near the planet Bajor, as the Bajorans recover from a decades-long occupation by the imperialistic Cardassians. The station is adjacent to a wormhole connecting Bajor to the distant Gamma Quadrant; the wormhole is home to powerful alien beings worshipped by the Bajorans as the godlike "Prophets", who have made Deep Space Nine's human captain Benjamin Sisko their "Emissary". The later seasons of the series follow a war between the United Federation of Planets and the Dominion, an expansionist empire from the Gamma Quadrant, which has already absorbed Cardassia.

This is the second episode of the nine-episode concluding story arc of the series, which brings the Dominion War and other story elements to a close. The episode follows several major plot threads. Sisko marries his fiancée Kasidy Yates, defying a warning from the Prophets that the marriage will bring sorrow; Gul Dukat, the former leader of Cardassia and now a worshipper of the Prophets' enemies, the Pah-wraiths, begins to win over the power-hungry Bajoran spiritual leader Kai Winn; and Deep Space Nine officers Ezri Dax and Worf are being held prisoner by the enigmatic aliens known as the Breen. Ezri is a member of the Trill species, symbiotically joined to the long-lived sluglike creature Dax; the previous host of Dax was Worf's late wife Jadzia, and the complex fact of Ezri's existence leads to complicated feelings between her and Worf.

The episode was originally to be titled "Umbra"; the title was changed to "'Til Death Do Us Part" in production.