Automated defensive particle cannon array is becoming real

In Summerville, Oklahoma, Egon Spengler captures an entity in occultist Ivo Shandor's mine outside of town and lures another to his farm. He activates an elaborate setup on his property, but the power fails. Egon manages to conceal the ghost trap in his home before being attacked by the entity and suffering a fatal heart attack before the entity returns to the mine. His estranged and financially struggling daughter Callie inherits the farm, moving there with her children, Trevor and Phoebe, after being evicted from their Chicago apartment. Trevor becomes infatuated with carhop Lucky Domingo and the scientifically minded Phoebe enrolls in a summer science class taught by seismologist Gary Grooberson, whom Callie later dates. Phoebe discovers the farmhouse is haunted and the invisible ghost residing in it leads her to the ghost trap, which she shows to Gary and her new friend, "Podcast". Gary, a fan of the Ghostbusters, helps her learn more about them and her grandfather. He, Phoebe and Podcast tamper with the trap, releasing Vinz Clortho, Keymaster of Gozer the Gozerian, who escapes to the mine. The farm ghost leads Phoebe to Egon's underground laboratory and, after revealing himself as her grandfather, guides her in restoring the Ghostbusters' equipment. While testing the proton pack with Podcast, Phoebe finds a ghost they call "Muncher" that haunts Shandor's foundry and flees to town. Having repaired the Ghostbusters' Ecto-1's engine with Egon's help, Trevor uses the car to chase Muncher with the duo; they capture him but are arrested for the damage incurred and their equipment is seized. Using the Ghostbusters' telephone number that she had written down, Phoebe contacts Ray Stantz for help, informing him of Egon's death. In turn, Ray tells her what became of the Ghostbusters following Vigo the Carpathian's defeat[b] – the team had disbanded following a downturn in business and Egon then moved to Summerville with all their equipment to pursue an unspecified threat. Shortly after, Gary is attacked and possessed by Vinz after returning the children home following a date with Callie. Egon leads Callie to a wall of detailed notes and pictures he kept of her life, showing he cared about her more than she thought. Soon after, she becomes possessed by Zuul, Gatekeeper of Gozer. Phoebe, Podcast, Lucky and Trevor find a Gozerian temple within the mine. Exploring further, they discover the long-deceased Shandor beginning to revive in his casket as automated proton cannons, installed by Egon, hinder Gozer's attempts to cross over. Vinz sabotages the cannons and performs a mating rite with Zuul, allowing Gozer to escape and take physical form. Shandor awakens and pledges his fealty to Gozer, but she immediately murders him. The children discover Egon's "farm" is an array of ghost traps buried in a dirt field. As supernatural chaos rages throughout town, they free Muncher and use him to recover the seized ghostbusting equipment and Ecto-1, then head to the mine. Phoebe distracts Gozer so Podcast can re-capture Zuul, freeing Callie and weakening Gozer's physical form. They lure Gozer and Vinz to the trap field, but it malfunctions as Zuul possesses Lucky when rescued, fully restoring Gozer's power. Ray, along with Peter Venkman and Winston Zeddemore, arrive to help as Gozer, having orchestrated Egon's assassination, seeks to resume avenging her previous defeat.[c] Supported by Egon's now-manifested ghost, Phoebe uses his proton pack to combat Gozer. The Ghostbusters assist by crossing their packs' proton streams while Trevor uses his to charge the traps' power source, allowing Callie to activate them and capture the villains. Lucky and Gary are freed from their possessions and Egon reconciles with his family and friends before ascending to the afterlife. In a mid-credits scene, the original Ghostbusters return to New York City and Venkman is revealed to be married to Dana Barrett. In a post-credits scene, Winston, having become a wealthy entrepreneur and family man since leaving the Ghostbusters, returns the fully restored Ecto-1 to the team's old firehouse headquarters. In the basement, a light on their old ghost containment system begins to flash red.