It's not Ghostbusters III
Rumors of a third Ghostbusters movie have persisted since the mid-'90s, despite the middling critical reviews and box-office receipts Ghostbusters II racked up upon its 1989 release. But the road to Ghostbusters III was paved with false starts, incorrect casting rumors, and many passive-aggressive quotes about Bill Murray refusing to read scripts.
And there were so many scripts! Dan Aykroyd has mentioned in interviews over the years that he wrote a version of the third movie with his frequent SNL collaborator Tom Davis, who also penned Coneheads with Aykroyd. That one, titled Ghostbusters: Hellbent, had the Ghostbusters going to Hell and, according to this 2002 script review, meeting a version of the devil that was a "Donald Trump-like mogul." Maybe the movie was just ahead of its time? (Note: Donald Trump appeared in the video for Bobby Brown's "On Our Own," the Ghostbusters II them song.)
In the intervening years, both Harold Ramis and original director Ivan Reitman have been linked to the project, with Ramis bringing aboard Office writers Gene Stupnitsky and Lee Eisenberg, who wrote his prehistoric Jack Black and Michael Cera comedy Year One, to put together a script. This was the script that everyone was trying to get Murray to read. In 2010, Murray absolutely ethered them in a GQ interview. "I never went to see Year One," he said. "But people who did, including other Ghostbusters, said it was one of the worst things they had ever seen in their lives. So that dream just vaporized."
It's a revenge picture
The movie focuses on a new set of Ghostbusters, played by Kristen Wiig (Bridesmaids), Melissa McCarthy (Spy), Kate McKinnon (SNL) and Leslie Jones (SNL). Here's a synopsis of the film, courtesy of the Boston Herald: "Wiig and McCarthy play a pair of unheralded authors who write a book positing that ghosts are real. Flash forward a few years and Wiig lands a prestigious teaching position at Columbia U... which is pretty sweet, until her book resurfaces and she is laughed out of academia. Wiig reunites with McCarthy and the other two proton pack-packing phantom wranglers, and she gets some sweet revenge when ghosts invade Manhattan and she and her team have to save the world."