Aykroyd said, "He's a good friend, I love him, but he just doesn't want to reprise the role. However, there will be a hole for him. If Billy wants to walk in the door and be in the movie, we will find a place."
While Bill Murray might not have an interest in Ghostbusters 3, Larry King said he would love to be a part of the movie. Aykroyd responded, "It's absolutely obligatory. Of course, you're going to be in the film."
Ghostbusters 3 will also star a new cast. Aykroyd explained, "We're going to have to cast. We need four new ghostbusters. We need four new Columbia students."
As far as the plot of Ghostbusters 3, Dan Aykroyd said, "It's based upon new research that's being done in particle physics by the young men and women at Columbia University." Aykroyd added, "Basically there's research being done that...I can say that the world or our dimension that we live in, our four planes of existence, length, height, width, and time, become threatened by some of the research that is being done. And ghostbusters, new ghostbusters have to come and some the problem."