After a paranormal encounter in her apartment, cellist Dana Barrett calls the Ghostbusters. She recounts opening her refrigerator and seeing a demonic dog-like creature that utters a single word: "Zuul." Ray and Egon research Zuul while Venkman offers to inspect Dana's apartment in a failed attempt to seduce her. The Ghostbusters are hired to remove a ghost from the Sedgewick Hotel. Having failed to properly pre-test their equipment, Egon warns the group to never cross the energy streams of their proton pack weapons as it could cause a catastrophic explosion. They capture their first ghost and deposit it in a containment unit in the firehouse. Paranormal activity rapidly increases across the city and the Ghostbusters become famous for their exploits; they hire a fourth member, Winston Zeddemore, to cope with the growing demand.