OK, i'm about to start a 'Trek miniseries--we made characters before Xmas, and it'll last until my roommate ships out, so we should get 5-6 [weekly] sessions. The intention is to plot out a contained plot in that timeframe (i'll compress or stretch in the middle, if i have to).
Here's what i've got so far:
Basic premise is that the Federation figures out a controlled way to move large masses to the Mirror Universe, sends a ship there to covertly look around, and the ship sent a mayday instead of meeting at its rendezvous point. The PCs are crew of a heavily-armed ship sent to retrieve them. Their mission is to rescue the others if at all possible, and make sure that those in the Mirror Universe don't find out about the Federation, or at least that there's a way to hop universes.
Tech level is DS9+ --timeframe isn't set yet, but i'm thinking shortly after the Dominion War. This would explain the UFP's relatively militaristic stance, and their extreme wariness about confronting a powerful new foe.
Oh, as for the Mirror Universe itself, i'm thinking of extrapolating from Mirror, Mirror, but not necessarily matching the stuff we saw in DS9. In particular, my gut feeling is to still have the Terran Empire aronud in some form as the major power. Haven't decided yet what to do with the other major races (subjugated, enemies, allies, etc.).
Now, i have two sorts of questions. Mostly, i'm wondering about tech. I want to equip their ship with the latest cutting-edge Treknology (appropriate to the era), since they'd want this ship to have the best possible chance of succeeding, and it's as on its own as anything could be. In fact, i'm thinking that the crucial element that makes universe-hopping possible either can't be put aboard a ship, or simply wasn't, so that should they be captured the Terran Empire won't be able to figure it out. So their only way back is to be at the right place at the right time, so that the device (in the UFP universe) can bring them back.
So, certainly quantum torpedoes, the latest phaser arrays, ablative armor, self-modulating shields...what else? What about personal equipment?
Now, what i want to do for the Terran Empire tech i basically take the literary device of the mirror universe to its logical extreme: use as many of the same events from the standard timeline (i.e., the TV shows & movies), but with slightly different feel or outcome. So, a changed event only has changed consequences when it's convenient for the plot. IOW, ramifications when i want them, but not otherwise. So, given a ruthless, opportunistic empire, what can i give them to make the players' lives difficult? Some initial thoughts:
Abuse the Guardian of Forever, rather than just leaving it alone once they rescue McCoy. Though maybe they let the peace activist live, thus producinga timeline (in the Mirror universe) where a more ruthless society is the precursor to the Eugenics wars, and eventually the Terran Empire.
Pull Data and/or Lore apart, find out what makes them tick, and make armies (or at least commando squads) of deadly super-soldiers.
Widely and ruthlessly use the Genesis Project as a weapon, on any planet they don't need for the resources. Perhaps all capital ships carry them?
Use the concept of the transporter-using slugthrower rifle as a standard personal weapon, or even expand it to torpedoes? Or is there something i'm forgetting that makes transporting [live] photon/quantum torpedoes impossible?
Conquer/co-opt/align with the Breen and swipe their energy-draining tech?
What other scary tech (especially weapons) did the various crews (especially Federation crews, i.e., Enterprise of one flavor or another) choose to nobly destroy so that none could use them? 'Cause the Terran Empire would probably grab every last one of those they could, and mass-produce those that could be mass-produced.
The other thing, which ties tightly into the tech, is any cool changes to the setting. Again, i don't want to actually take these things to their logical extremes, and consequences only follow when entertaining (thus leaving the universe a "dark reflection", not a completel ydifferent place). Frex, how would things go when the Mirror universe Enterprise found the Botany Bay?