The narrative of Playing Gracie Darling commences in 1997, as a motley crew of teenagers huddled within a secluded cottage nestled deep within the forest's embrace. Through the ominous medium of a Ouija board, they summoned the spirit of Levi, a being whose presence shrouded the room in an otherworldly aura. As Gracie dared to inquire about the spirit's demise, Levi's response sent shivers down the spine of the teens. The glass on the board danced with an insistent frenzy, compelling Anita and Jay to scramble for the exit. Joni and Gracie held fast, only for Gracie to suddenly convulse on the floor, her lips repeating the spirit's unsettling plea to be released. Joni, too, bolted from the cottage, leaving Gracie alone in her terror.
The narrative leaps forward twenty-seven years to the present day, where Joni now serves as a psychologist for the police force. After a taxing day where an inmate inflicted self-harm with a paintbrush, Joni returns home to find her daughters, Mina and Lulu, sitting by the side of her mother, Pattie. Pattie indulges in a tarot card reading for Mina, remarking on her daughter's resemblance to Joni and her innate concern for others' approval. Joni's defenses rise, and she retreats to speak with Jay, who calls out of the blue.
Jay's news sends shockwaves through Joni's composure – another member of the Darling family has gone missing. He reveals that he and Anita's daughter, Raffy, were playing Gracie Darling with Frankie Darling in the very same cottage where the events from twenty-seven years ago unfolded. Joni's shock is palpable but quickly subsides as she turns her attention back to her children. Over dinner, she chats with Mina about her upcoming break, savoring every moment with her girls. Yet, as she retreats to her thoughts alone, Joni is consumed by memories of that fateful night in the cottage with Gracie. Leaving a note for her mother, Joni slips into her car in the dead of night, her mission clear: to uncover the truth behind the missing girl and the unsettling past that threatens to resurface.
Joni returns to her hometown, where she reunites with Jay, a dedicated cop whose words carry weight about Frankie's ongoing issues with the Darling family over Gracie's fate. Their journey leads them to meet Jay's wife, Anita, who welcomes them with open arms. Joni attempts to engage Raffy, the one who has been silent since the incident, feeling empathy for their guilt over leaving Frankie alone in the cottage. She discloses a chilling revelation: Levi's spirit has invaded Frankie during their game.
As they drive back, Joni and Jay discuss Levi's presence, with Joni urging him to let Raffy speak at her own pace. Before departing for home, Joni makes a stop at the Darling residence, where she encounters Frankie's grandmother, Moira. They catch up, but Moira's call to Ruth, Frankie's mother, results in an argument that prompts Joni to leave.
As she exits, Joni peeks into Gracie's old room, transporting her back to the days when she frequently visited the Darling household. A flashback depicts Joni making a makeshift Ouija board for Gracie after her arm fracture. Gracie's grandfather enters the room, and the girls quickly hide the board. He invites Joni to stay for dinner before departing.
In the present day, Joni searches under the fireplace in Gracie's room and finds the mixtape she made for her friend. She takes it with her and plays it in her old house, transporting her back to a time when her parents, Bob and Pattie, were still together but often in disagreement. Young Joni often escaped their arguments by hanging out at the cottage with Gracie, Jay, and Anita.
Returning to the cottage now, Joni recalls the night of Gracie's disappearance when the four friends gathered there. They spot Billy hiding, eyeing adult magazines. Joni feels a presence within the cottage and suddenly finds herself outside, witnessing a flock of birds exiting in a frenzy.
Joni visits the church to talk to teenagers but is met with Zac, the pastor, who requests her not to engage with the kids without a permit. That evening, Joni tells Pattie about her decision to stay in her old town to confront the incident head-on.
Later that night, a piercing scream rent the air, and Joni discovered a burning effigy in the midst of the street. Jay, racing to quell the flames, urges Joni to steer clear of the investigation. The next morning, Joni's eyes alighted upon Zac at the convenience store, observing him purchase condoms. Meanwhile, a woman strolling with her dog in the forest brought a discovery to the police station—something her loyal companion had unearthed.
Later still, Joni joined the other cops in their search for Frankie, only to stumble upon a young girl's pursuit. Her discovery of charred bones sent shivers down her spine, and she hastily sought assistance. She reached out to her mother over the phone, relayed the gruesome detail, and paid a visit to the Darling household, extending her condolences.
To Joni's surprise, she found Zac there, praying alongside Moira. Just then, Jay arrived with the news that the charred remains belonged to a girl whose forearm bore the mark of a fracture. The episode concluded with Moira's shock at uncovering Gracie's remains after all these years, her heart reeling with unspoken sorrow.
