Prom Night 2 firstly does not hold any comparison to its predecessor starring Jamie Lee Curtis.
We begin in 1957 where Mary Lou Maloney is caught cheating at the Prom by her boyfriend Billy. Unfortunately Billy takes his jealous a tad too far and ends up accidentally setting Mary Lou on fire on the stage of the prom.
Fast forward 30 years later and the spirit of Mary Lou has returned to the school where Billy is now the Head Teacher to gain some revenge.
Whereas the original owes a lot to Halloween, the sequel has more in common with another slasher Nightmare on Elm Street and even to some extent Nightmare 2.
Because of the horrific nature of her death, Mary Lou’s soul is not yet at rest and can possess people in able to gain her revenge.
The death count is actually quite low for a slasher film, but when people are taken off the roster so-to-speak; it’s done in brutal fashion.
These including being fried by a computer and being choked to death and thrown out of a second storey window.
It now becomes a race against time for the adult Billy and Father Cooper (who was also at the 1957 Prom) to find a way to stop the spirit of Mary Lou before it becomes another Prom Night to forget.
As previously stated it is a different storyline to the original, but considering this is the way that John Carpenter wanted to go with sequels to Halloween; it is quite refreshing to see a sequel so diverse.
It won’t be everyone’s cup of tea but most horror films based in the 80s weren’t either.
Paul Downey's Blog 
It’s crazy how every sequel to Prom Night goes in a different direction. Nice write-up.