''Star Trek VI: The Undiscovered Country'' is not much more than a murder mystery in space, but it works.
You may figure out the identity of the villains long before being told, but the film is as entertaining as it is big, partly because of its humor.
Most ''Star Trek'' feature films have had some humor, but this one seems to be smarter than the others.
The players (and the producers) may be sending up their very sturdy vehicle, which has carried the cast for 25 years, but this is a cautious kind of humor. The laughs are bright without relying on put-downs.
For instance, Captain Kirk tells Mr. Spock that he is of the opinion that all those aboard the Enterprise are human, to which Spock replies: ''I find that rather insulting.''
The film uses its laugh lines wisely and to great advantage.
The original crew is back for ''the final adventure of the Starship Enterprise.''
You don't want to take any of this too seriously. They said that about the last ''Star Trek'' movie.
The ''Star Trek VI'' plot plays on current headlines. When the film begins, Klingon, having depleted all its ozone, is destined to expire in about 50 years. This makes the Klingons more receptive to peace with the Federation, so Klingon leaders contact the Enterprise.
A short time later, a Klingon leader is assassinated. When Spock and Kirk become the chief suspects, a trial takes place.
If you care to know the rest, see the film, which, like all sci-fi movies, worms its way out of situations that may seem silly to some but never to Trekkies (or Trekkers, if you prefer).
At times, ''Star Trek VI'' looks a little like a ''Mad Max'' movie. Those are its worst moments. Fortunately, they are few. At other times, the writers borrow from some of the episodes in the original series. You'll also see traces of ''Star Wars,'' ''2001: A Space Odyssey,'' ''Manchurian Candidate'' and ''Outland,'' but what does it matter if it all works? In this instance, it does.
William Shatner continues as Capt. James T. Kirk. Leonard Nimoy is Mr. Spock. DeForest Kelley, James Doohan, Walter Koenig, Nichelle Nichols and George Takei reappear in their familiar roles, all looking as if they are enjoying this latest adventure.
Do they seem a little too old to be on the Enterprise? Isn't Mick Jagger a little old to be prancing and preening on the concert stage the way he does?
Kim Cattrall is the female Vulcan who serves as detective when the crew looks for the killers. Iman is the sorceress Spock and LTC Kirk meet. David Warner and Christopher Plummer are Klingon leaders.
''Star Trek VI: The Undiscovered Country'' opens at local theaters today. Climb aboard. Enjoy the trip.
''Star Trek VI: The Undiscovered Country'' *** The Klingon empire wants to make peace with the Federation, but when the Klingon leader is assassinated, Captain Kirk and Mr. Spock are the chief suspects.
CAST: William Shatner, Leonard Nimoy, DeForest Kelley, James Doohan, Walter Koenig, Nichelle Nichols, George Takei, Kim Cattrall, David Warner, Christopher Plummer and Iman.
DIRECTOR: Nicholas Meyer.
RATING: PG (violence).
RUNNING TIME: 107 minutes