The morning after the attack on the evacuation center, Mitchell picks up surveillance footage from a gas station showing two of Carroll's men abducting Parker. She identifies one man as Alex Lipton, a militia warrior. As they try to work out the clues Carroll has left them, Ryan sees a young boy wearing a Poe mask walk up to the station. The boy, Jack Foster, says that a woman named Emma paid him $20 to put on the mask. Realizing that it's another clue, Ryan checks the mask and finds a phone number inside.
The team calls the phone number and reaches Debra, buried in a coffin in the woods. She tells them the route that Alex and the other cultist took her and Ryan promises that they'll find her. Mike tries to work out the probable route that they took but warns Ryan that there are thousands of acres of woods. He figures they only have three to five hours until Debra runs out of air. Turner stops in and tells them that they found Alex's car.
Claire wakes up and finds herself in a cabin near the ocean. She runs outside and discovers that she's next to a lighthouse like the one in Carroll's novel. He comes out holding a gun and orders her inside, and she points out that the ending of his story, set in a lighthouse, is predictable. Carroll insists that's a motif but Claire derides his talent and dares him to kill her. He refuses because he wants Ryan to get there and bear witness to Claire's death so that it will do him in. Claire doesn't believe it and Carroll says that he's had enough of her. He shoves her in a room and locks her in, and someone in the room moves toward Claire.
Ryan and the others pull up to Alex's car and discover that it has a flat tire. As Turner begins a search, Ryan realizes that Alex cut the tire himself and figures that he wants them to find it. Alex opens fire from the woods, aiming at Mike but hitting a passing FBI agent. Everyone takes cover and Ryan goes charging into the woods while the others provide cover fire. Ryan gets behind Alex and orders him to drop the weapon. Alex denies knowing anything about Debra and Ryan pistol-whips him. When they take Alex back to the SUV, Ryan tells Turner that they'll take him back to town by themselves. Well aware of what Ryan intends, Turner tells him to do what he has to.
Claire talks to the man with her, Neil Meyer, who explains that two kids hired him to bring a boat up. They broke his ankle so he couldn't run, and wonders what is going on. Neil is shocked to learn that Carroll is their captor and figures that he'll kill both of them.
Ryan and Mike pull off the road and take Alex to an abandoned shed. Mike explains that they're going to beat him until he talks. Alex doesn't believe them but after a few punches, he tells them that he buried Debra. He refuses to say anything else and Mike picks up a metal pole and breaks his leg. The cultist finally caves and gives them directions, and Mike calls it into Turner. Ryan assures Alex that he'll kill him if they find out that they're lying and drag him back to the SUV.
At the lighthouse, Neil and Claire try to break off the boards over the windows without success. Carroll comes in and orders Claire out. She asks him to let Neil go but he refuses and drags her out, locking the door behind him. When she suggests that he let Neil go, Carroll considers killing his prisoner. Claire points out that Ryan might not make it in time, but Carroll is confident that he'll follow the trail that he's set for him. He insists that the two of them were good together but Claire tells him that love was a lie. After thinking about it, Carroll tells Claire that he'll miss her when she's gone.
Ryan and Mike drive to Debra's location and Turner warns them that his men can't get there any sooner. They're still ten minutes away and Ryan has Mitchell patch him through to Debra. Ryan tells Debra that they're heading for her location, and she asks him to call her sister Beth and her parents and tell them that she loves them. Debra admits that they're not close and it's her only regret. Mike tells her to stop talking and save her air, and Debra says that he's a good man and that he shouldn’t lose that. As her air runs out, Debra tells Ryan that she chose to join the BFI and it's not on him.
Mike pulls up to the spot and Ryan drags Alex out and has him direct them to the buried coffin. They find the spot and start digging, and Alex tells them to hurry. Once they hit the coffin, they dig it clear and wrench up the lid. Debra is inside but she's not breathing, and Ryan performs CPR. He finally gives up, realizing that they're too late, and Alex gloats about her death. Ryan walks over to him and shoots the cultist dead before Mike can stop him.
As Ryan looks down at Debra's corpse, he notices an envelope in the coffin. It's Carroll's book, describing exactly what happened and how they would get there too late to save Debra. The book says that Alex shot Mike in the woods, and they realize that they can still change the story. Ryan keeps reading and discovers an address that he's supposed to go to. He tells Mike that it's for him alone and it's his fight, but Mike insists that it's his fight. Ryan warns him that Carroll wants everyone close to him dead, and draws his gun and tells him to stay there. Mike doesn't believe that he'll shoot but Ryan fires a warning shot into the ground and drives away.
Carroll asks Claire when she knew that he liked killing young girls. She says that she didn't know until he was arrested, and that she was the one who sent Ryan to Carroll as a consultant. Carroll doesn't believe her and she bursts into tears, insisting that she was blind to the truth. He finally apologizes, saying that denial is a powerful thing, and comes over to her. Claire blames herself and Carroll reassures her that she's the victim. He drags Neil out onto the floor and stabs him repeatedly, and then tells Claire that's what it's like to actually kill someone. Carroll tells Claire that she killed no one and that he doesn't want her taking responsibility for his actions because he owns them.
Ryan drives to the house in the manuscript and turns to the final chapter, and discovers that there's nothing there. Emma is standing inside the garage and tells him to lose the gun and phone. Ryan does so and walks inside, and she orders him to kneel. When he hesitates, Emma says that she's been instructed to shoot him if he doesn't obey. When Ryan refuses, another cultist grabs him and injects him with a knockout drug.
When Ryan wakes up that night, he hears the ocean in the distance. Carroll greets him as Claire looks on, and Ryan tells Claire that everything will be okay. The cult leader figures that they'll write the final chapter together, and says that he's been talking with Claire about her poor choice in men. Ryan asks what his part is in the final chapter and Carroll tells him to admit when he fell in love with Claire. The FBI consultant isn't sure, and Carroll figures that it was love at first sight, the same way that he fell in love with Claire. When Carroll insists that he and Ryan are connected, Ryan says that it isn't by love. Carroll asks when he first suspected he was the killer, and Ryan says at first that he followed him. However, he finally admits that he followed Claire to see if she would lead him to Carroll. That was when he fell in love with Claire.
Carroll says that the fact that Ryan and Claire are in love will make things easier and prepares to kill his ex-wife. Ryan says that it's too predictable and insists that Carroll kill him, but Carroll says that he has to fulfill Ryan's death curse. Despite that, Ryan continues, saying that it will be overkill and saying that Carroll was never a competent writer. He continues to insult Carroll and says that he's bored with him and Edgar Allen Poe, dismissing the writer as a trumped-up morphine addict. Carroll lunges at him and Ryan struggles with him and shoves him aside. He grabs the gun and fires at Carroll, who runs out, and Claire tells Ryan to find him and kill him.
Ryan chases Carroll to the boathouse and his nemesis attacks him from behind. They struggle for the gun and it goes off, hitting a gas tank and starting a fire. They struggle and Ryan shoves Carroll into the flames. The roof comes down on top of Carroll and Ryan gets out just as the boathouse explodes. Claire runs up and hugs Ryan, and they both watch the boathouse collapse into the waters.
The next morning, the FBI secures the area dredge the nearby waters for the body. They've found partial remains and have a dental match, but won't know for sure until they do a complete autopsy. Mike tells Ryan that the FBI has reached out to Debra's family and that they have seven cultists in custody. Claire gets a call from Joey in D.C. and Ryan says that he'll fly her there and make sure she stays safe. Once they're alone, Ryan asks Mike if he's okay. He says that he isn't.
Later at Ryan's apartment, Claire watches the news while Ryan gets a call from the coroner confirming that the body they found was Carroll's. They kiss for a moment and then Claire goes to get cleaned up.
In Mobile, AL, Emma is wearing a wig for a disguise and watches the news at a restaurant. When they announce that Carroll is confirmed dead, she breaks into tears and runs out.
As Ryan puts some music on, there's a knock at the door. He answers it and his FBI guard gives him the food that he ordered. Carroll takes it to the kitchen and cuts it open with a knife, and hears another knock at the door. There's no one there and Carroll closes the door and locks it. When he goes to get the knife, he discovers that it's gone... and Molly emerges from the shadows and stabs him in the stomach. She tells Ryan that Carroll promised that she could have him. Claire comes in and Molly stabs her while Ryan watches.