The Klingon Empire is on the brink of collapse and a plot threatens peace talks with the Federation.
Star Trek VI: The Undiscovered Country, released in 1991 and directed by Nicholas Meyer, takes place after a catastrophe on a Klingon moon that leaves the Klingon Empire in danger. The Federation and the Klingons begin to negotiate a peace, and Kirk, who has long distrusted the Klingons, is sent to escort the Klingon chancellor to a conference on Earth.
When the chancellor is assassinated and Kirk and McCoy are accused of the murder, they are sent to a prison planet. Spock and the crew of the Enterprise-A work to find the real conspirators, who include officers on both sides who do not want peace. The story is a political thriller that reflects the end of the Cold War and asks whether old enemies can change. Kirk has to confront his own prejudice and his grief.
The film was the last to feature the whole original cast and was intended as a farewell to the crew. It ends with the Enterprise-A being retired and with the crew signing off. It is regarded by many as one of the strongest entries and as a fitting end to the original crew's story.