Some rich, white assholes in Africa in the 1950's are attacked by some sort of monster conjured with tribal magic.
Does anyone remember that episode of TV's Doug where the titular character was too afraid to watch a horror movie because he didn't want to see the monster at the end, but when he finally sees the movie the monster turns out to be a man in a fake, corny looking rubber monster suit? Well, this is essentially that movie.
I'll say this, all of the Curse "sequels" were better than the original, but it's still a pretty weak "series." To be fair to part 3, although it never grabbed me, it seems like a genuine attempt to build suspense was made on the part of the filmmakers. It still has the crass violence and nudity you'd expect, but there's some sort of reach for class or respectability in the way it keeps the monster offscreen for as long as possible and tries to build an ominous air of mystery around it. In that sense, it's like an updated version of an old 50's scary movie (perhaps explaining why the film is set in that era)... but it lacks the spooky fun of the best of those films.