[DS9] Season 3, Episode 19: Through the Looking Glass
This is a fun episode! Leave it to Deep Space Nine to add some complexity to mirror-universe stories, which started out being 100% silliness. Not that this episode is silliness-free, or that the mirror universe episodes ever become really good, but they do get a lot more interesting starting with “Through The Looking Glass”.
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Read more at Memory Alpha
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Notes:

The mirror-universe Sisko died, and O’Brien needs Sisko to stand in for him and convince Jennifer to stop building super sensors for the bad guys.

Sisko and O’Brien purposely get themselves captured, and Rom gets to the station as well, by pretending to be a snitch for the bad guys

But Sisko knows the command codes to initiate the self-destruct sequence. Luckily they’re the same as in the normal universe.
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