stay and scream is a hhn ticket which is cheaper than the regular ticket.
you must have purchased the regular universal/ioa ticket for that day of the hhn event.
now, you are in the park for the day.
the park closes at 5:00. you don't have to leave. you will go to a designated area and be able to enjoy the park (limited area) from closing time (5) to opening time of hhn (7).
you might be fortunate enough to be able to do a few of the houses before the general public comes in.
now if i have left anything out, please jump in and add to what i posted.
Bascially, if you have some form of HHN pass (regular, FFP, etc) then you can utilize Stay & Scream as long as you're in IOA and go to the lockdown area(s).
The boys and I were planning a mini Dec trip but now I think our mini trip is going to be moved to Oct. We loved HHN last year and this year with both parks I just dont think I can miss it, lol.