Ghostbusters II is a 1989 film starring Bill Murray, Dan Aykroyd, Sigourney Weaver, Harold Ramis, Rick Moranis, Ernie Hudson and Annie Potts, directed by Ivan Reitman, written by Ramis and Aykroyd and produced by Reitman.
Plot
After saving New York City from the demi-god Gozer, the Ghostbusters are sued for property damage and barred from investigating the supernatural, forcing them out of business. Five years later, Ray Stantz owns an occult bookstore and works as a children's entertainer with Winston Zeddemore, Egon Spengler works in a laboratory conducting experiments into human emotion, and Peter Venkman hosts a psychic television show. Peter's ex-girlfriend Dana Barrett has had a son, Oscar, with an ex-husband, and works at an art museum.
After Oscar's carriage is drawn to a busy intersection by an unseen force, Dana turns to the Ghostbusters for help. Dana's boss Janosz Poha is possessed by the spirit of Vigo the Carpathian, a sixteenth-century legendary tyrant trapped in a painting in the museum. Vigo orders Poha to locate a child that Vigo can possess, allowing him to return to life.
Under the intersection where Oscar's carriage was possessed, the Ghostbusters discover a river of slime filling the abandoned Beach Pneumatic Transit line. After obtaining a sample, Ray is attacked by the slime and accidentally causes a citywide blackout. The Ghostbusters are arrested and found guilty of investigating the supernatural. In the court room, the slime taken as evidence reacts to the judge's angry outburst and releases the ghosts of two deceased convicts. The Ghostbusters capture the ghosts in exchange for the restraining order being rescinded.
The slime invades Dana's apartment and attacks her and Oscar. She seeks refuge with Peter, and the two renew their relationship. The Ghostbusters discover that the slime reacts to emotions, and suspect that it has been generated by the negative attitudes of New Yorkers. While Peter and Dana have dinner, Egon, Ray, and Winston explore the underground river of slime. They are pulled into the river and escape coated in slime. They begin arguing, and Egon realizes that they are being influenced by the slime. They learn the river flows to the museum.
The Ghostbusters go to the mayor with their suspicions, but are dismissed. The mayor's assistant, Jack Hardemeyer, has them committed to a psychiatric hospital to protect the mayor's interests. A spirit resembling Janosz kidnaps Oscar from Peter's apartment, and Dana pursues them to the museum. After she enters, the museum is covered with a barrier of impenetrable slime.
On New Year's Eve, the slime rises to the streets, causing widespread paranormal activity. The mayor fires Hardemeyer and has the Ghostbusters released. Determining that they need a symbol of positivity to rally the citizens and weaken the slime, the Ghostbusters use positively-charged slime to animate the Statue of Liberty and pilot it through the streets before the cheering populace. At the museum, the slime recedes and they use the Statue's torch to break through the ceiling.
Janosz is neutralized with positively-charged slime, but Vigo immobilizes the Ghostbusters and attempts to possess Oscar. A chorus of "Auld Lang Syne" by the citizens outside weakens Vigo, returning him to the painting and freeing the Ghostbusters. Vigo momentarily possesses Ray, and the other Ghostbusters freed him from his grip. Louis attacks the weakened slime barrier with a proton stream of his own. Vigo is destroyed,and the painting transforms into a likeness of the Ghostbusters protecting Oscar. The Ghostbusters receive a standing ovation from the onlookers and the Key to the City from the mayor.