Stories have to move forward. If you were chart out the plot progression of a successful genre film, you'd probably find lots of curves and loops and the occasional cul-de-sac, but overall, the thing would progress from left to right fairly steadily. Too much back-tracking and you gunk up the works, too much stalling and all those delicate lies and concessions that make a fictional world real start to collapse under their own weight. If you've ever been to the movies and found yourself checking your watch around the two-thirds mark, you'll get what I'm talking about. (And it's such a definitive moment, too, like somebody in your head flipping a switch between "Interested" and "So, how much is left?")
One of the things that makes Star Trek III: The Search For Spock such an odd duck is that the entire movie is, in a sense, its own cul-de-sac. Our leads aren't trying to save the world or defeat some terrible enemy (although there's a little of that last near the end). They're just trying to return to the status quo that the climax of Star Trek II: Wrath Of Khan overturned. It's like the first act of Return of the Jedi stretched to feature length, only instead of rescuing Han Solo from the clutches of the universe's most dastardly giant slug, here we've got Kirk, McCoy and the rest fighting against time to get Spock's body and Spock's soul (or "katra") reunited. Ostensibly this is to preserve his knowledge back on Vulcan, but I can't imagine anyone thinking we weren't going to hit the end credits without seeing Nimoy doing that eyebrow thing again. There's precious little that's new in Search; in fact, the film rejects the idea of innovation, either mocking it (with Scott's easy monkey-wrenching of the Excelsior) or actively negating it, with a conclusion that not only restores everybody's favorite Vulcan to life, but also destroys Khan's two biggest additions to the mythology: Kirk's son David, and the planet Genesis. In many ways, it's an entry with a calculated design on longevity. "Don't worry," we're reassured. "These guys may look old, but they've still got some miles left in them. We'll be watching them do the same things in slightly different ways for many years to come."
And yet for the life of me, I can't find it in myself to dislike Search. Sure it's redundant. Sure, it wastes the momentum of the first act with a climax so rote you can almost hear the writer admitting defeat. But it's fun, by and large. There's something charmingly old school in its machinations, and while its ambitions aren't terribly, well, ambitious, it's still a decent time-waster, and a nice bridge between the space opera weightiness of Khan and the light absurdity of Star Trek IV: The Voyage Home. Its main flaw is that it never entirely justifies its existence; Spock's death was a satisfying, moving capstone to the series, and to undo that for no better reason than "just cuz" is always going to come off weak.
One thing that's easy to forget, especially if, like me, you grew up watching this; Search takes place right on the heels of the end of Khan, which makes the sudden shift in Shatner's toupee especially jarring. (Whatever you do, don't look at it too long. It kills the whole movie.) With David and Saavik (a flatly wooden Robin Curtis; Kirstie Alley wanted too much money to return to the role) already headed back to Genesis for study, it's left to Kirk and the others to mourn Spock in their own way. One of the better aspects of Search is that with Spock out of the action, the rest of the crew gets a chance to fill up the vacuum of his absence, and we get a much stronger sense of Kirk, Uhura, Chekov, McCoy, Scotty, and Sulu as a family unit, and not just a bunch of people who work together. Seeing everyone in Kirk's apartment, mourning the loss of their friend, creates a warm glow that covers up a lot of the movie's weaker moments.
Of course, that connection doesn't stop Kirk from hustling everyone out when Sarek arrives. (At Sarek's request, of course.) We've talked before about the odd juxtaposition of mysticism and clinic-ism in Vulcan culture, and once again we've got intellect (in this case, Spock's katra, his essential self) being preserved by an arcane ritual that we, as outsiders, never completely understand. Obviously this is just as much goobledy gook as is necessary for resurrection, but it has a nice thematic ring to it. And it allows McCoy to get his own minor subplot. As Kirk himself discovers (via some suspiciously well-edited security footage), Spock passed his essence to McCoy before dying, which means we get Nimoy dubbing in some off-screen lines that are supposedly coming from DeForest Kelley's mouth, as well as having McCoy's personality shift ever so slightly to the pointy-eared. Bones' clumsy attempt to book passage back to Genesis in the Starfleet equivalent of Mos Eisley is great, as is his reaction to learning what Spock did to him: "It's just his revenge for losing all those arguments."
Search isn't as overtly comedic as Voyage Home, but it gets a brief charge out of the ensemble being witty and kicking ass. The best bit of the whole film is when Starfleet tells Kirk he can't go back to Genesis for "political reasons," and Kirk decides he'll just take the Enterprise anyway. With a little help from his friends, of course. Search is Leonard Nimoy's first time in the director's chair for the franchise, and he goes out of his way to make sure that everybody gets a chance to shine: Sulu beats up a guard twice his size, Uhura locks a bratty ensign in a closet, and Scotty gets to take-down that new-fangled spaceship that everybody's so keen on. (Chekov gets screwed, I guess, but at least he has a whole sub-plot in Voyage to himself.) If Khan was about Kirk coming to terms with getting old, Search is about celebrating seniors. It's ridiculous, but I find myself grinning every time.
The rest of the movie can't quite keep up the pace; it never turns into a slog (although I still find the sequence back on Vulcan where Spock gets brain back fairly dull), but it's predictable. There's a crazy Klingon named Kruge (Christopher Lloyd doing his best John Lithgow) who's become obsessed with the secrets of Genesis. He destroys the ship that David and Saavik hitched a ride on, then sends a couple of thugs down to the planet to menace them face to face. As scene-chewing as Kruge is, he's mostly just a missed opportunity. We've already had a larger-than-life character railing about Genesis, and no matter how much spit Lloyd sprays, he's nowhere near as interesting and threatening as Montalbahn. Story-wise, the only reason he's around at all is so Kirk gets to fight somebody in person for once (and what a pathetic, anti-climactic fight it is; makes you appreciate the fact that Kirk and Khan are never face-to-face), and so that David can sacrifice himself heroically. Oh, and so the Enterprise can get blowed up real good.
Of course, just bringing up the katra concept wasn't going to be enough to get Spock back—otherwise Vulcans would be functionally immortal, and that probably would've come up before now. Instead, we have the Genesis planet somehow resetting Spock's body, making him young and then aging him as the planet ages. It's one of those things that makes a kind of surface intuitive sense, but doesn't hold up at all under scrutiny. Why would his corpse de-age and then age again? If Genesis is some kind of fountain of life (would this work on any corpse? Does it only work a little while after the planet's created? If enough time had passed, and if the planet hadn't been destroying itself, would Kruge's dead crewmembers turn into baby Klingons?), that would seem to have some pretty serious ramifications on things. Thankfully, the planet tears itself apart before anyone can really think about it.
Search for Spock is basically for fans-only, and for once, I don't mean that in an entirely pejorative sense. What you get out of it depends entirely on how much you care about these characters, and how much of a charge you get at the very end, when Spock is back to (sort of) himself. He's befuddled, but he eventually recognizes Kirk, and then he does that eyebrow raise… I dunno. I'm not sure I'd go so far as to agree with "The needs of the one outweigh the needs of the many," but it has a nice ring to it; and if I'm honest, I'll admit that Star Trek without Spock isn't really Star Trek at all.