In the 23rd century, the Starship Saratoga encounters a huge craft like a pillar in the sky that is headed for planet Earth. Any attempt to communicate with it fails, and more concerning than that is the fact that is drains the spaceship's power, placing them in jeopardy. Back on Earth, Admiral Kirk (William Shatner) is being tried in absentia for his recent crimes against both Starfleet and the Klingon Empire, with the Klingons especially determined to bring him to justice for the loss of one of their crews. On the planet Vulcan, Kirk and his shipmates make plans to return to face the music, but they will find more pressing problems - that probe is still heading for their home...
Star Trek IV: The Voyage Home is generally considered the best of the series of films they made, probably because it's a lot friendlier than the others, and more accessible to the less convinced with it. It was the most successful of the franchise to that date, and with Leonard Nimoy returning both as Spock and to the director's chair, there's a cosy sense of old pals reuniting to entertain us in a plot that makes much use of the touchy-feely side of eighties environmentalism. This is due to the narrative hingeing around a be nice to the whales topic, very much in vogue in 1986, as it is now to some extent, but back then it felt a lot more cutting edge.
The whales enter into this because of the probe, as when it arrives at Earth it starts evaporating the seas and causing cataclysmic storms, and all because nobody can work out what it wants. Leave it up to Mr Spock and his brilliant mind to fathom that it is searching for someone to communicate with, and with the crew of the now-destroyed Enterprise zooming across space to the rescue, he realises that what is needed is a humpback whale or two to reply to the probe, as this is the language it is "speaking". Only trouble with that is, humpback whales have been extinct since the twenty-first century, and all because of mankind's relentless hunting of them - are you getting the message, modern day mankind?
If it's more than a little heavy-handed in its do-goodery, then at least the film conveys it with a genial air. For the initial half hour you'd think this was the usual, earnest Star Trek business, all wrapped up in itself as ever, but once the Klingon ship Kirk has comandeered takes a trip around the sun at many times the speed of light, they end up back at 1987, which is handy for the production designer because they don't need to build quite so many sets if the cast are to be acting in actual locations of the time. Those locations are around San Francisco, where a pair of humpbacks named George and Gracie are about to be released back into the wild, which is perfect for the needs of the future.
One of the most satisfying things about The Voyage Home is that none of the veteran crew are there for the sake of turning up, as they all work as a team very convincingly, giving the stars the chance to have a bit of fun with not only derring-do, but comedy as well. So Chekov (Walter Koenig) does not go down too well as a Russian asking about "nuclear wessels" to everyone in earshot during the Cold War, and Spock gets to use his knockout neck pinch on an errant punk rocker who was playing his music too loud. All very amusing, and perhaps more accomplished than the more sincere aspects, yet Spock's recognition that he needs feelings as well as logic in order to be a more balanced individual plays well with the wider need for humanity to add compassion to their science and progress, particularly when it comes to preserving their planet. Elsewhere Shatner turns on the charm to woo marine biologist Catherine Hicks, and there's a decent running gag about how far advanced the fictional future is compared to the eighties, so if it's patently high concept, that concept was a winning one. Music by Leonard Rosenman.