"Yes! Genesis! How can you be deaf with ears like that?"
There is a wisdom as old as time that says "There is no such thing as a good odd-numbered Star Trek movie." While we could get bogged down in arguing minutiae, I would rectify that statement and say that there is no great odd-numbered Trek film, but there are at least two good ones, and the best of the odd-numbered Treks is arguably Star Trek III: The Search for Spock.
Forming the middle portion of a trilogy with Wrath of Khan and The Voyage Home, Search for Spock picks up immediately after the events of Khan, with the Enterprise crew still mourning the loss of their former Captain Spock (Leonard Nimoy). Upon returning to space dock, the crew is given a commendation and extended shore leave (except poor Scotty, who has to report to the new Excelsior engine room to help with their transwarp drive). The crew is resigned to the fact that the Enterprise, being over twenty years old, is going to be decommissioned, but a visit from Spock's father Sarek (Mark Lenard) leads Kirk (William Shatner) to believe that while Spock's body may be dead, his consciousness is alive in someone else... Dr. McCoy (DeForest Kelley).
Kirk and a skeleton crew (Scotty, Sulu, Chekov & Bones) set out in the Enterprise to return to the Genesis planet and retrieve Spock's body, in hopes of returning it to Vulcan. What they have yet to find out, however, is that Lt. Saavik (Robin Curtis) & Kirk's son David Marcus (the unfortunately named Merritt Butrick) have discovered, on Genesis, that Spock has been reborn as a child. Further complications arise when a Klingon ship, commanded by Kruge (Christopher Lloyd) gets wind of the failed Genesis project and travels there in hopes of stealing the technology for the Klingons.
Okay, we need to get this out of the way immediately; The Search for Spock is not a very good film, even by Star Trek standards. It suffers from horrendous budget restrictions which first time director Nimoy couldn't shoot around as well as his predecessor, Nicholas Meyer. A lot of the recycled sets & costumes look terrible, and really distract on the 2009 blu-ray high def transfer. It's likewise hindered by being sandwiched between arguably the two best Star Trek films ever made, and can't help but feel like a trifle compared to the other two. It's got more substance than I remember it having, but the stakes are relatively low from beginning to end, and the sense of danger imposed by Khan in the previous film is just not met by the Klingons in this film.
All that being said, the film is actually much better than I remember it being, if for no other reason than the script is actually surprisingly well written. The dialogue and interplay, particularly between the Enterprise crew is as good as it's been in any of the films, and the humor throughout (much of it by, or at the expense of, Bones) is pretty reliably funny. The two truly emotional moments in the film (Kirk learning of the death of David & Spock's recognition of Kirk at the end) still land incredibly well and make up for some of the more ridiculous acting choices made by the other actors throughout the entire film.
William Shatner, the actor, was never better than he was in these three films. His moment I mentioned a moment ago, learning of the death of his only son, is very powerful and as good as he's ever been on screen. He also appears to be having a good deal of fun in this film, which is odd considering he was unhappy at having to be directed by his co-star (all of which led to Shatner taking the helm of arguably the worst Star Trek film not directed by JJ Abrams, Star Trek V: The Final Frontier). The rest of the crew is good as well, of course all resigned to one or two bits (one of the few lessons Abrams & his writers wrongly incorporated from the original films).
Lloyd is also nowhere near as bad as I remember him to be. His casting is ridiculous, to be sure, but he's not quite as bad in actuality as I seemed to have thought he was. Curtis, taking over the role of Saavik from Kirstie Alley, though, doesn't fare as well. Granted she's not given much to do, but her line readings are spotty at best and she's not terribly convincing as a Vulcan. Beyond some ridiculous stunt work in the final fight between Kruge & Kirk on the dying Genesis planet, there's really not much else bad I can say about the film.
Star Trek III is a fairly lightweight effort in the Trek canon, but it still manages to have far more good moments than bad, and is ultimately a genuinely enjoyable entry in the series. It has its flaws, to be sure, and they are numerous, but it still manages to be solidly entertaining and never insulting in the way some of the other odd numbered Trek films were. It can't help but pale in comparison to the two films bookending it, but I wholeheartedly recommend checking it out, particularly if it's been a while since you've seen it. It holds up much better than you might remember.
[Photos via TrekCore]