So, after the events of part 2, the Ghost Busters are buried in law suits, etc from the city due to all of the destruction of property (including a national monument). They break up, Ray moves home but takes his toys with him in hopes of one day returning to busting. Egon goes back to his studies, during which time he becomes ill and passes, Winston, being tired of all the publicity, etc surrounding having been a part of the crew moves off in an attempt to disappear, and Peter moves in with Dana.
Current day, Dana has passed, Peter shares an apartment with Oscar (now in his mid 20's), one day, Oscar comes home to find Peter dead with a message scrawled on a sheet "Gozer"....
Que title card