-Spoiler Warning-

The first version of the film was shown in theaters.

The second version was shown on all home video formats. This version includes a couple of additional footage to certain key scenes, and a few new scenes all together.
- Spock has more Dialogue in the top brass meeting.
- A scene taking place in the President's office where Col. West presents his plan to sneak into Klingon territory and rescue Kirk and McCoy.
- Spock and Scotty checking the torpedo inventory before Valeris informs them that the Chancellor's Daughter is now the current klingon chancellor.
- The klingon assassin at the climax of the film turns out to be Col. West.

The Third version of the film is shown on this Special Collector's Edition DVD. This version includes all the material from the second version, and a few minor changes to certain scenes and effects.
- When Martia gets shot, a disruption sound effect is removed to make her scream more apparent.
- Valeris's interrogation scene has been entirely reedited. There are now close up shots of Kirk and McCoy when they speak their lines instead of being in wide shots. When Spock and Valeris name a particular conspirator, the face of that person briefly appears in a flashback like style.

Do I prefer this version of the film? Sure. I personally believe that Valeris's interrogation scene is much more dramatic with the flashback shots. It really helps the viewers who aren't good with names understand who Spock and Valeris are talking about, and adds a little more tension near the end of the film.

I hoped this information helps you out in spotting what has been changed. If there is anything I missed, please feel free to contact me.

Coming on the heels of the less-than-stellar Star Trek V: The Final Frontier and the resignation of Harve Bennett as producer of the feature films, Paramount turned to actor/producer Leonard Nimoy and director/screenwriter Nicholas Meyer (Time After Time, Star Trek II: The Wrath of Khan) to save the foundering franchise and give fans something worthy of a 25th-anniversary celebration. After looking at various options, they decided on a Star Trek version of the end of the Cold War.

The Undiscovered Country (the title is a Shakespearean reference to death and was Meyer's first choice for the title of Star Trek II) capitalizes on the similarities of the U.S.-Soviet standoff to the long-standing not-quite-war between the Federation and the Klingon Empire. Fittingly, the film begins with a bang when, in a Chernobyl-like accident, the Klingon's main energy production source on the moon of Praxis explodes.

The explosion sends both literal and political shock waves across the galaxy. The physical subspace wave buffets the USS Excelsior, now commanded by former Enterprise helmsman Hikaru Sulu (George Takei). Capt. Sulu, in the tradition of good Starfleet captains, offers assistance but is rebuffed by the Klingon High Command.

Nevertheless, three months later, Sulu's former shipmates, including Capt. Kirk (William Shatner), Dr. Leonard "Bones" McCoy (the late DeForest Kelley), Capt. Montgomery Scott (James Doohan) and Cmdrs. Uhura (Nichelle Nichols) and Pavel Chekov (Walter Koenig) are summoned to a top secret level meeting. "The Klingon Empire," they are told by Starfleet's commanding admiral, "has less than 50 years to live." Praxis' explosion has depleted the ozone layer of the Klingons' homeworld and polluted the atmosphere. Heavy expenditures on weapons and bases has weakened the Klingon economy and the cleanup is beyond their means. A special envoy has been appointed by the Federation to begin negotiations with Chancellor Gorkon, leader of the Klingon High Council. To the shock of Kirk and his officers, that envoy is Enterprise first officer Spock (Leonard Nimoy).

And when Kirk is assigned to escort Gorkon's ship into Federation space for a summit on Earth with the Federation president (That 70's Show's Kurtwood Smith), he's shocked and angry. Not only are the senior officers due to retire in a few months, but Kirk is still bitter about his son's death at the hands of the Klingons several years before. But the good captain has been issued his orders, and like it or not, he will do his duty.

Little does he know that a massive conspiracy to undermine the peace negotiations is underway, planned by those in the Federation and the Klingon Empire who have a lot to lose if peace breaks out. And soon, Kirk and the Enterprise crew are caught in a web of deceit and intrigue that will place their lives in jeopardy....and shatter the last best hope for galactic peace.

The film features a fine performance by Sex in the City's sultry Kim Catrall as Lt. Valeris, Spock's full-Vulcan protege with a hidden agenda of her own, as well as a wonderfully over-the-top appearance by Christopher Plummer as a dastardly, Shakespeare-quoting Klingon general. The Undiscovered Country also acknowledges the legitimacy of Star Trek: The Next Generation, and with an appearance by ST-TNG actor Michael Dorn as Col. Worf (the grandfather, one surmises, of the Enterprise-D's Lt. Worf, Dorn's "regular" role), the two generations are bridged on the silver screen. ("Unification, Parts I and II," guest starring Leonard Nimoy, had aired a few weeks before the film's premiere and included a few subtle references to its storyline.)

Star Trek VI's home video, laserdisc and first DVD releases contain the longer edited-for-home-viewing version which includes two deleted scenes featuring Rene Auberjonois (who would later be cast as Odo in Star Trek: Deep Space Nine) as Col. West. Paramount has released a barebones DVD since 1998, but a 2-disc Collector's Edition is forthcoming.