I said god damn, this was excellent! Probably the best college/sorority/campus slasher ever.
A sorority house is about to throw a massive party, much to the dismay of their conservative house matron. Eventually the sisters decide to play a prank on the matron that accidentally ends with her death.
As the night rages on, the sisters become paranoid that someone will discover the body they dumped. But they have much bigger things to worry about when they all start to get picked off one by one...
This came out in 1983, when the slasher craze was in full effect but was just starting to die out. It was getting harder to come up with original plots and this film does it spectacularly.
My only major complaint is we never got the sequel that it was so clearly trying to tease. Oh, well. Not everyone can be Jason.