The sixth episode of "Playing Gracie Darling" begins with a flashback as Frankie discovers a Bible with notes hidden beneath Gracie's bed. What transpired the night Frankie disappeared? Inside the Bible, Frankie sees the name "Levi Darling," his birth year, and the names of other family members. Leaving Gracie's room, she runs into a drunken Ruth, who engages in an argument that ends with a slap. Peter's appearance further infuriates Frankie, who is exhausted by the Darling family's secrets. She storms out, and Peter follows, but she yells at him to leave her alone.
Frankie seeks solace at the cottage where Raffy is waiting. They drink and Frankie vents about her family, eventually leading to her disappearance as they play the "Gracie Darling" game.
Present-day Joni wakes up in Jay's bed and rushes home, remembering returning with Gracie's necklace after her disappearance. She asks Bob for the necklace he claims to have stored, sparking a heated argument between them. Joni admits her memory of that night is foggy, which sends Pattie into a panic.
Joni searches for the necklace and finds it in her room. Inside, she discovers pictures of herself and Gracie, making her sad for doubting their friendship. She secludes herself in a dark room, watching a hypnotism video to unlock memories. Later, she tells Jay she remembers hurting Gracie during a seizure.
Joni goes to the woods where she initially saw Gracie's bones, hoping to find something. She returns home, shocked to learn that Mina is missing. Joni searches the town and questions Raffy and Anita. Anita reveals that on the night of the incident, Jay showed up at her house hours later with clothes soaked in blood.
The truth about what happened to Gracie unfolds as she flees when Gracie is convulsing, returning to the cottage to find Gracie still "possessed" by Levi, begging to be let out. Gracie jumps on Jay, and in the ensuing struggle, Gracie hits her head and bleeds. Panicked, Jay flees to find Anita. In the present, Joni tries to reach Jay but receives a call from Raffy about Mina wanting to go to the cottage.
Mina finds herself at the Darling house, her inquiries to James about Levi's whereabouts only to find the man consumed by a fit of agitation. Hallucinations of Levi burning in the cottage take hold, and in his confusion, he mistakes Mina for Gracie, dragging her to the shed and forcing her to kneel, demanding a confession.
Joni, desperate at the cottage, tries to summon Gracie, her visions of a drowning girl in the shed haunting her every step. She rushes to the shed, only to hear Mina's screams behind the door. Breaking in, she sees James attempting to drown Mina. Peter arrives just in time, pulling James away while Joni saves Mina.
But what truly happened to Gracie? After hitting her head, she wakes up and stumbles home. James finds her outside, questioning her about getting drunk. Her mockery and mention of Levi trigger James, and he drags her to the shed, punishing her with prayers and repeated dunks in the water. In a fit of rage, he kills Gracie just as Peter and Ruth arrive to witness the horror.
As for Frankie, with James taken to the hospital, Moira is devastated. Jay visits Billy at his houseboat, asking about Frankie. Billy reveals he has been hiding her in an abandoned property. She refuses to return home, terrified that James killed Gracie. Joni tells Moira that James may never get a trial due to his mental state and age, and in a fit of rage, Moira suffocates him with a pillow.
The show ends with Joni burying Gracie's necklace at the cottage and seeing the turbines flying overhead in an infinity symbol. She tells Jay she's leaving town, and he reveals having confessed to pushing Gracie on the night. Joni is proud of his honesty but warns that something dark is still lingering in the cottage. Back home in the city with Pattie and the kids, Joni spots Ivy inside her house. Ivy, the same girl who tried to stab herself in custody, suddenly vanishes. Joni calls her colleague, who reveals that Ivy died by suicide a few days earlier.
