Ask any Trekkie and he'll tell you about the odd-even rule: odd-numbered Trek movies embarrass the franchise, while even-numbered Trek movies justify our faith in it. The biggest exception to this rule is Star Trek III, which had the unenviable task of following up the high point of the entire phenomenon, but otherwise does quite well for itself. It marked Leonard Nimoy's debut as a feature film director, keeping his hand in the action even though his character is largely absent. That actually makes a sweet deal for him: everyone spends the whole movie talking about Mr. Spock and he doesn't have to show up until the final scene.
The search for Spock is obviously the purpose of the exercise (it's right there in the title), and it makes for a hell of a narrative challenge. We just finished the last movie with his wrenching, heroic death -- leaving tears on every cheek and a sense of appropriate finality that the rest of the series never matched -- and now we get to watch him come back? Star Trek III has to perform that resurrection without invalidating the emotional punch of Star Trek II. In that sense, putting Nimoy behind the camera was a smart move. No one has a bigger investment in the character than he, and no one else could hit the proper beats with such precision.
And so we're off again, as the crew of the Enterprise defies orders and steals their ship to retrieve their lost comrade from the now-forbidden Genesis planet. Said planet provides an easy answer for Spock's return to life, as well as explaining what Kirk's son David (Merritt Butrick) and the Vulcan Lt. Saavik (Robin Curtis) have been up to since the end of Star Trek II. Curtis endured heaps of scorn from the Trek faithful for having the audacity to replace Kirstie Alley in the role, but in truth she does quite well in combining cold logic with implicit compassion. The vitriol she's had to put up with speaks volumes about how cruel Trekkies can be sometimes, and how blind they are to their own bullying tendencies.
Butrick does decently too, though his character's rather arbitrary death constitutes one of the film's biggest missteps. Having witnessed William Shatner's admirable restraint at the end of Star Trek II, he promptly loses his shit when the time comes for a curtain call: hammy, over-the-top and about as emotionally convincing as a plastic Santa Claus. Even without the scenery chewing, it makes David’s presence here one of plot contrivance rather than real character development
You can see the challenge that dogs this film at every turn. Each moment gets held up to its predecessor by default, evoking comparisons that it can't quite live up to. But that process also means that the film earns its merits as well as its shortcomings. We rarely derive as much joy from the supporting crew members as we do here, freed from the constraints of military protocol and indulging in full-bore rebellious mischief for the first time. The bad guys carry some heft too: this is the only time outside of the original series that we get to see the Klingons as full-bore villains, and led by Christopher Lloyd's understated commander, they don't disappoint.
Then there's the destruction of the Enterprise itself, which takes place about two-thirds of the way in and constitutes the film's big money shot. It's a stunning image, and more importantly, it carries a hefty emotional punch that doesn't try to compete with its immediate predecessor (while further emphasizing Kirk & Co.’s willingness to do anything for their friend).
It doesn’t quite make for a classic, but it's definitely classic Trek, and as the middle third of an impromptu trilogy (II, III and IV), it does the heavy lifting that helped make The Voyage Home such a romp. Not many Trekkies would list The Search for Spock as their first viewing choice, but it rarely lets you down, and even its weaker moments still belong quite firmly to Gene Roddenberry's unique creation. It also manages a nice little emotional payoff to close out the proceedings, courtesy of Nimoy himself. Star Trek III moved under the radar amid the more prominent movies in the Summer of '84, and by refusing to compete with them it performed a neat little end around. It resolutely remains its own beast, concerned only with maintaining the legacy that other Trek films worked so hard to establish. Considering some of those other odd-numbered movies, its victory is no less astonishing for the occasional flaw.