It's basically the brother of the killer in the first movie's story. He's in a mental institution and get's interviewed by a doctor about why he's in there.
But they end up recapping like 30-45 minutes worth of part 1's footage, so its barely a movi, but the footage they do add is just classic:
http://www.youtube.com/watch?v=i7gIpuIVE3k
Definitely not a "good" movie, but nonetheless enjoyable. The actor seen above is easily one of the worst actors of all time.
-D