The day before the murders, Reese spends a miserable night on the screened-in porch, too stubborn to go inside. She texts her friend Skylar a picture of a taxidermy fish, but Skylar leaves her on read and later replies dismissively. The next morning, Reese argues with her younger sister, Mae, over a borrowed sweatshirt. Their mother, Emily, intervenes and takes Mae’s side.

At the pool, Reese finds the day cold and boring. Reese notices Elliott staring at her in a way that she interprets as both inappropriate and flattering. As she leaves for the cottage, an unknown man makes a suggestive comment.

Walking through the woods, Reese witnesses her brother, Wyatt, completing what appears to be a drug deal with an older man. She knows that Wyatt sells his prescription Adderall for profit. Taking a different path to avoid him, Reese grows frightened when she hears approaching footsteps. A male figure emerges from the trees, telling her not to be scared.

Elliott reports that Detective Evans questioned him about his fishing trip and his relationship with the victims. Courtney shares what the children told the detective. She asks why Emily wanted to speak privately with Elliott. He claims not to remember this conversation.

Courtney feels numb and distracted. She tries to eat but vomits again. Unable to get cell reception inside the cottage, she climbs a nearby hill and attempts to call Reese, reaching only an automated voicemail. Checking Reese’s Instagram, she discovers all posts have been deleted. She phones Emily’s mother and her own parents to deliver the devastating news. Alone on the hill, she breaks down sobbing before a police officer appears from the woods and orders her back inside for safety.

As night falls, a police cruiser is stationed outside for protection. Elliott prepares macaroni and cheese for dinner. While changing, Wyatt reveals a large bruise on his chest. Cass and Mae ask to sleep with Courtney. Mae confesses she misses her mother. Courtney comforts both girls. Mae cries herself to sleep.

Courtney lies awake past two o’clock in the morning, terrified. She hears a noise and finds Wyatt on the sofa bed, looking at his phone. He tells her he knows where Reese is.

The figure in the woods is Daniel, a resort employee. He and Reese flirt and bond over having difficult mothers. Daniel asks about Reese’s home life, and she confides that her parents constantly fight. Their conversation is interrupted when Nolan and Emily pass nearby, arguing loudly. Reese and Daniel hide as Nolan tells Emily she is ruining everyone’s vacation. After the couple leaves, Daniel asks Reese to meet him that night on the pier after her parents are asleep. Despite uncertainty about whether she can sneak out, Reese agrees.

Wyatt shows Courtney Reese’s location on Snapchat’s Snap Map, indicating she is only five minutes away. Courtney immediately calls Detective Evans. He is skeptical about the map’s reliability but agrees to organize a search. He forbids Courtney from joining the overnight effort, insisting she stay with the other children.

The next morning, police organize a ground search with community volunteers. Courtney decides to participate, leaving Elliott with the kids. Elliott admits he cannot stop thinking about Reese’s last argument with Emily. Though he does not say it directly, Courtney senses he suspects Reese may have killed her parents. She defends her niece but privately acknowledges the teenage Reese has become almost a stranger.

As Courtney leaves, the police officer stationed outside asks where she is going. She tells him about the search, then drives away, feeling as though she is being watched.

The night of the murders, Reese sneaks out of the cottage to meet Daniel. She carefully opens the door without making noise, leaving it unlocked behind her because she has no key. In the dark woods, she becomes frightened when she hears a noise and sees a figure approaching. A hand clamps over her mouth. It is Daniel, who unnerves her by suggesting she should not have trusted him.

Courtney arrives at the search location near a waste disposal site. Detective Evans advises her to manage expectations and prepare for the worst. The search begins with volunteers calling Reese’s name. A woman tells Courtney that another volunteer, Joanna, lost her daughter years ago. Courtney approaches Joanna and her husband, Sam Matthews, both gaunt with visible grief. Joanna explains that their 11-year-old daughter, Kylie Matthews, vanished five years earlier and was never found. There were suspects but no body and no resolution. She tells Courtney the worst part is not knowing what happened, adding that even terrible answers would be better than none.

Daniel reveals he was only joking about hurting Reese and admits he is high. He says he grew tired of waiting at the pier and came to find her. They flirt as they walk deeper into the woods. Daniel calls Reese beautiful, which flusters her. Remembering advice from her friend Skylar about playing hard to get, Reese deflects his advances. Daniel offers her a joint, and despite her limited experience with marijuana, she smokes with him.

They arrive at a cemetery, which Daniel claims is haunted. Both hear a strange noise from the woods that frightens them. Though scared, Reese insists she does not believe in ghosts. Daniel comforts her and then kisses her.

During the search, volunteers discover the decapitated and decaying carcass of an animal, not Reese. Courtney collapses in momentary relief before despair returns. After the search ends, Joanna and Sam offer their contact information and support.

Detective Evans walks Courtney to her car and reveals critical information: The person Reese met, Daniel, is 24 and has not shown up for work in two days. He tells her the cause of death was blunt force trauma from a Louisville Slugger baseball bat found outside the cottage with blood and fingerprints on it.

Courtney returns to the cottage at dusk. When Elliott opens the door, startling her, she drops her keys. Retrieving them from the deck, she notices what appear to be specks of blood on Elliott’s fishing shoes. Cass and Mae ask if she found Reese; crushed, they retreat to the loft when she says no.

In their bedroom, Courtney confronts Elliott about the blood. He reacts angrily, asking if she thinks he is the killer, then says it must be from bleeding the fish. After he falls asleep, Courtney uses his iPad and discovers multiple photos of Reese in a bikini by the pool. The final image shows Reese flipping off the camera with a defiant expression. Courtney remembers that day: Shortly after taking the photos, Elliott had come to the cottage and initiated urgent sex with her. She now suspects his arousal was triggered by Reese, not her.

After returning from the cemetery, Reese finds Wyatt waiting on the screened-in porch. He reveals he followed her and Daniel and shows her photos and video footage he recorded of them together, including their kiss. When he tries to blackmail her for $20, Reese becomes enraged and humiliated. She tackles him to the floor, kneeling hard on his chest and causing a large bruise, and grabs a shard of glass from a broken lantern, raising it to stab him. She recalls a previous violent incident where she gave Wyatt the scar above his eye. Wyatt fights back, pushes her off, and taunts her before increasing his blackmail demand to $40. After he leaves, Reese lies shaken on the floor, reflecting on her past diagnosis of intermittent explosive disorder.

Late that night, Courtney wakes and goes to the kitchen for water. Wyatt appears, sleepwalking. In his confused state, he believes it is a school morning and becomes agitated when he cannot find his lunch. He threatens Courtney, saying he will kill her if he is late for school. When she tries to gently wake and guide him back to bed, Wyatt reacts violently, slapping Courtney hard across the face. He prepares to strike again, but Courtney screams, waking Elliott and the girls.

The commotion wakes Wyatt, who is disoriented and frightened. He says he dreamed someone was trying to take him. Courtney lies to Cass, claiming she bumped her face on a door. A police officer knocks; Elliott tells him it was just a nightmare. In the bathroom, Courtney sees a large bruise forming on her cheek in the shape of Wyatt’s hand. Elliott is shocked when he sees her injury. Courtney defends Wyatt, explaining he was terrified and dreaming. Back in the bedroom with Cass sleeping between them, Courtney asks Elliott to lock the door.