Star Trek VI: The Undiscovered Country (1991)

I mean, there are better Star Trek movies, but this was 1991 and the Berlin Wall fell and the Klingons were the metaphor for the USSR (despite what the current everything is political writers of Picard say, despite their attempts to invert it) and spray cans destroyed to O-Zone layer...
... and so do moons.
So.... this fit PERFECTLY into 1991. PERFECTLY, and good science fiction is always a commentary on politics, culture, religion, something contemporary that needs to be poked at and examined.
And that is EXACTLY what VI does, and it does it to the letter. It examines the old cold warriors in a new time of peace.

Fresh from their flirtation with the Almighty, our crew of intrepid explorers are on the eve of hanging up their phasers when they are summoned to carry out one last mission. This time, it's just a courtesy job to escort the Klingon High Chancellor to a conference on Earth. They meet, have a nice state dinner and exchange some Shakespeare; next thing the Klingon has been assassinated and "Kirk" and "McCoy" have been fitted up for the crime and imprisoned on a cold penal colony that makes "Hoth" look like Barbados. Now we have a race to free them and get to the new venue of the peace meeting before the warmongering "General Chang" (Christopher Plummer, complete with a bolt-on eyepatch) and his Federation co-conspirators put the kibosh on the proceedings and they all die fighting. This is the last ensemble outing for the whole crew and it's a great bit of action adventure in the spirit of "Wrath of Khan" (1982). A fitting finale for their last voyage together.