Before a few nights ago, I'd never seen the old STAR TREK movies (I know; shocker). I saw THE VOYAGE HOME on a shelf, and, knowing that the plot was independent of the others, picked it up and watched it. I was wowed; it was sharp, funny, intense, and intelligent. This one...not at all. If you're hoping to watch the first to gain character knowledge: you won't get it. In fact, you're better off starting with number two.
That said, there's little objectionable content. People are vaporized (their forms are seen screaming before they disappear), and there are some "d**n"s and "hells".