Joy spends some time with her friends, and returns to find Annie in a frenzy. Abdi takes Pop to the hospital, and Ace talks with a real estate agent.
Annie gets out of her SUV and goes into the cabin, as Ace stares at her, unmoving. Inside, Annie locks the door and stares out the window, and Joy asks what she's looking at. Ace has disappeared, and Annie clutches at her head, wondering if she hallucinated him.
As Bobby barks at him, Abdi jumps up and breaks the chair he's tied to. He frees himself and runs as Bobby pulls the leash out of the unconscious Pop's hand and runs after Abdi. Abdi lures the dog into the elevator, gets out, and slams the door closed, trapping Bobby inside. He then drives the unconscious Pop to the hospital and has two orderlies take Pop inside.
The next morning, Annie nervously looks out the window but there's no sign of Ace. She makes sure that Joy is sleeping, then writes a note to her daughter and leave it on the table, saying for Joy to start packing and she's going to work. Annie then drives back to the construction site and discovers that the sinkhole has been concreted over. She sees the Marsten House up on the hill and drives there, and goes inside. Annie looks around, unaware that someone is watching her from the shadows.
Continuing into the House, Annie finds a padlocked door. She hears a noise behind her and turns to find Hassan in the kitchen, eating raw eggs shell and all. He looks at his liquid-covered body and shouts in Somali, and Annie runs out.
At the hospital, Pop wakes up in a bed and finds Nadia standing over him. She tells him that he had a mini-stroke and asks him what happened before Abdi brought Pop there. Abdi hasn't returned her calls, and Pop says that Abdi should have left him there. He says that he hurt Abdi and asks if he's okay, but then says that he doesn't know what he did to Abdi. Nadia goes off, leaving another voice mail for Abdi.
At the motor lodge, Joy is drawing when Chance knocks at the door. She invites Joy to come with them to look for a dead guy, comes in, and asks if Annie is there. Joy says that Annie is at work, and Chance says that they're going to look at Castle Lake for Ace's body. Joy says that they're going to be leaving Castle Rock, and Chance tells her to keep the phone and call her later. As she starts to go, Joy says that she'll come with her and Chance tells her to bring a bathing suit... or not.
Joy, Chance, Timothy, and Vera hike through the woods to the lake, joking and eating snacks. When they get there, they take a boat out.
Annie calls Nadia and asks what mix of pills the doctor gave her. She says that she's having visual hallucinations, and Nadia tells her to come in but she has a family emergency.
Vera talks about how her father was at Shawshank and then sent to Ohio when they shut down the local prison. She mentions that Chance is emancipated and Joy talks about all the rules Annie has to protect her. Joy finally starts swearing despite Annie's rules against it, and realizes that Chance puts marijuana in the snacks. Timothy drops the oar, and Joy jumps in to get it.
Later the teenagers return to the motor lodge. Timothy and Vera leave, and Chance tells Joy that she was bad-ass. Joy says that she's feeling normal again, and Chance tells that's too bad. She leans forward, tells Joy to keep her phone on, and goes into her cabin. Joy goes into her cabin and starts to apologize to Annie, and discovers the interior is torn up. Annie is in the bathroom staring off into space, and says that Nadia poisoned her. She tells Joy that the pills made her do a bad thing, and that Joy has to hear her out. Annie says that she killed Ace because he came there and threatened them. She cleaned up the blood so well that she can't find a speck of it, and then Ace came back. Annie stares out the window, and Joy takes a syringe out of Annie's purse. Her mother talks about how she tries to be her best self when she's with Annie, and Joy wonders if Annie imagined it. Annie warns that Ace will come back again, and asks Joy if she believes her. Joy says that she does and Annie hugs her... and Joy injects her with the sedative.
Abdi meets with Nadia and says that he should have let Pop die. His sister tells him he doesn't want that on him, and Abdi explains that he saved Pop because Nadia cares about him. He says that he didn't see the look on her face that she had when their mother died, and Nadia puts her head on his shoulder.
Ace enters Pop's hospital room and greets his uncle. Ace says that firebombing Nadia's house was a mistake, and Jamal tells Pop to take it easy while Ace says that his whole life has been a mistake and backs out of the room. Ace goes to the restroom, looks at himself in the mirror, and then leaves. He drives down to the road in his tow truck, drinking, and hits the accelerator. Officer Andersen pulls him over for speeding and Ace gives him the finger. Andersen comes over, gun drawn and yells at Ace to get out.
Annie wakes up and finds herself tied to her bed. In the kitchen, Chance texts Joy to tell her that nurses saw Ace at the hospital. Annie calls to Joy, begging her to untie her, and Joy ignores and text her that Annie wasn't mad at Joy going out. Joy comes in and asks Annie if she's ready for her pills. Her mother says that they never talked about what an emergency was, and Joy tells her that it's an emergency when Annie sees things that aren't there. Annie insists that they're not the right pills, but Joy says that she checked them. Her mother insists that the pills are wrong so the plan is off, and tells Joy that she'll take the pills. Joy feeds her a pill and makes sure that Annie swallowed it, and says that she'll untie Annie when she's ready. She says that Ace is still alive and leaves the bedroom. Once she's alone, spits out the pill.
Real estate agent Valerie Blount drives to the Marsten House, and Ace comes up behind her as she gets out. She knows about Ace, and she takes him in to see the House. Ace knows that the original owner was a Satanist and killed himself, and asks Valerie if she can still have children. They go in and Valerie sees that squatters have been living there. Valerie goes to look for them and finds Andersen in the bathtub, covered in goo. He crawls out, and Valerie turns to see Ace behind her, holding a chain.
Annie hallucinates Ace breaking Joy's neck and choking her. She snaps out of it, gasping, and sees an empty glass on the nightstand.
That night, Joy reads to Annie and then prepares to go to bed. Annie says that she used to read to her father but jumbled up the words, and Joy asks what's in her mother's lockbox. Her mother says that they're just papers, but Joy demands to see the contents. The timer alarm goes off and Joy gives Annie another pill. Annie says that she feels better and thanks Joy, and Joy goes out and looks up the topic of visual hallucinations on the Internet.
Annie manages to reach the glass and put it under her pillow, then breaks it with her head. Joy comes back in with a sandwich, and asks her to tell the truth about everything. She asks what they're running from, and Annie finally says that Joy's father didn't want her and she did. Annie took Joy and she ran, and didn't expect the police to understand what he was. She says that she didn't want Joy to be afraid, and says that Joy's father is coming for them and won't stop. Annie admits that she lied to Joy about how her father died in the war, and insists that everything she does is because she believes in a better world. She talks about how the sun rises when she looks at Joy, and Joy is her better world. Annie says that she'll do the worst things to protect Annie from the monsters and feel fine about it, because the only thing that matters is Joy.
Joy notices the dead mice on the floor, dead from when they ate the pills Annie spit out. She finds one of the pills and realizes that Annie lied to her again. There's a knock at the door and Annie begs Joy not to answer. Joy doesn't believe her and goes out, slamming the door behind her. Annie grabs a piece of glass with her teeth and tries to reach the ropes on her wrists, but drops the shard.
There's more knocking at the door.
Annie cuts her mouth and right arm with the glass as she grabs it with her teeth and tries to cut herself free. She dislocates her left shoulder and sobs in pain.
Joy opens the door, and Nadia asks if Annie is there. Joy says that Annie is sick and can't come to the door, and Nadia asks if everything is okay. The doctor says that Annie was having some serious symptoms, and Joy tells Nadia that she doesn't know anything about Annie and closes the door.
Annie cuts her right hand free, grabs a glass shard, and cuts at the rope around her left wrist. Joy comes in and tries to stop her, and Annie slashes her across the arm by accident. The girl runs out, and Annie finishes freeing herself. She runs outside and calls to Joy, but there's no sign of her daughter. The Tall Man walks forward, and Annie runs back into her cabin and closes the door. She goes into the bedroom and takes the pill on the floor, and the bedroom door opens and closes. Annie stands up, and the Tall Man tells her that the story ends with Annie killing Joy.
- Lizzy Caplan as Annie Wilkes
- Tim Robbins as Reginald Merrill
- Garrett Hedlund as John "Ace" Merrill
- Elsie Fisher as Joy
- Yusra Warsama as Dr. Nadia Omar
- Barkhad Abdi as Abdi Omar
- Matthew Alan as Chris Merrill