The happyish ending of the first one is undone in a matter of minutes when Martin, the survivor of the first movie, has his wife and child taken by a new powerful sentient vampire leader who controls the religious nutjobs from the first movie.
He then searches the wastelands for Mister, his protégé vampire killer. They meet in a cannibalistic Thunderdome and fight their way out. They then find another group of survivors and prepare to battle the religious nut jobs and their leader, all of whom have it out for Mister.
The bleak and misery from the first one is laid on pretty thick early on here but there are a few more characters and some lighthearted moments, like the relationship between Steven Williams and A.C. Peterson which was a nice touch.
The 64th October horror marathon movie was a pretty good sequel that builds off the original, adds some mythology but doesn't overcomplicate things.