Mike Schmidt, a former mall security officer, finds himself in a difficult situation after losing his job for assaulting a father he mistakenly believed was trying to abduct a child. In a bid to secure a stable future for himself and his younger sister, Abby, he consults career counselor Steve Raglan, who offers him a job as a night guard at the eerie, long-closed Freddy Fazbear's Pizza. Although hesitant at first, Mike is driven to accept this offer when social services threaten to place Abby under the care of their estranged aunt, Jane, due to concerns about his emotional well-being.
On his first night, the haunted memories of his past resurface. Mike dreams of the tragic abduction and supposed murder of his brother, Garrett, who was taken from him by an unidentified figure. In this nightmarish vision, he encounters five ghostly children who witnessed the crime but flee from him in terror. By his second night, he meets Vanessa Shelly, a police officer who provides insights into the restaurant's dark history—it shuttered after the unsolved murders of five children in the 1980s. Despite the dread that envelops him, Mike attempts to confront one of the ghostly children only to be attacked and left injured, though Vanessa is there to treat his wounds.
As the nights progress, Jane schemes to undermine Mike by employing a group of delinquents to vandalize Freddy Fazbear’s, hoping to get him fired and regain custody of Abby. During this chaos, the iconic animatronics—Freddy, Chica, Foxy, and Bonnie—spring to life and begin to viciously murder the intruders. In a shocking twist, among the delinquents is Abby's babysitter, Max, which compels Mike to bring Abby along on his next shift.
As the animatronics show a peculiar affinity for Abby, Mike grows concerned about their sinister nature. It soon becomes evident that these creatures are possessed by the spirits of the murdered children, led by a blonde boy who consistently references a "yellow rabbit." In between his shifts, Mike tries to uncover the truth about Garrett's disappearance, a lingering cold case that haunts him, and admits to taking sleeping pills to revisit these disturbing dreams.
Conflict arises as Vanessa warns Mike against bringing Abby back to Freddy’s, prompting Mike to leave her in the care of Jane while he seeks answers during the day. Unfortunately, an overdose on his sleeping pills leads him back into a dream where the children tempt him with the promise of reuniting with Garrett, but only at the expense of Abby. In a twist of fate, Jane is brutally murdered by Golden Freddy, a twisted apparition of Freddy Fazbear, who takes Abby captive once more.
Mike battles through his own horrifying dreams, culminating in an escape from a torturous fate just as Vanessa comes to his aid. As he recounts the relentless horrors, Vanessa reveals shocking connections: she's the daughter of William Afton, the notorious serial killer responsible for the original murders, controlling both the animatronics and the spirits therein. Realizing the imminent danger to Abby, Mike races to the diner equipped to disable the deadly machines.
In a heart-pounding climax, Chica tries to harm Abby, but with quick thinking, Mike manages to disable most animatronics and rescue her. However, chaos ensues as Afton—disguised as Steve Raglan—attacks and reactivates the animatronics. In a bold move to expose the truth, Abby draws a picture depicting the murders, which stirs the spirits of the animatronics against Afton. As he faces inevitable death, his suit malfunctions due to the animatronics' rage, leading to his gruesome demise.
With the immediate threat vanquished, Mike and Abby manage to escape with Vanessa, who succumbs to a coma and is rushed to a hospital. The siblings return to their lives, forever marked by the horrors they've encountered. In a haunting mid-credits scene, Golden Freddy watches Afton’s lifeblood seep away, sealing off his fate, while a post-credits tease reveals Balloon Boy lurking inside a taxi, hinting that the dreadful legacy of Freddy Fazbear's Pizza might not be over.
