A trucker parks outside a diner and listens to a radio report of a killer on the loose. The suspect is a sandy haired man with a rose tattoo on his arm. The trucker eyes an attractive waitress, then sees a man matching the suspect's description stepping out of the diner and following a teenage boy. The trucker draws a gun and follows the man to the back. A growling is heard and the trucker is thrown out by something.
Nathan and Audrey arrive at the diner. Audrey is still a little down about breaking up with Chris. The trucker says he didn't see who attacked him, but it clearly had superhuman strength. Dwight arrives and convinces the trucker that he was attacked by a bear. The witnesses identify the boy the killer had been following as Rory Campbell and there is a trail of blood leading into the woods. The waitress called Rory's parents and his father is on his way. Audrey and Nathan enter the woods and find a wristband that says "Forever". They figure they should search by themselves since there isn't a lot of people they can trust.
Rory's father shows up and insists he join the search, as he is an ex-Marine and refuses to let a killer get away or leave his son in danger. Dwight says he wants to join as well. Nathan warns him that it is too dangerous, since Dwight's Trouble attracts bullets toward himself, but Dwight insists. Audrey calls Duke and asks for his help. He refuses, but she says the adventure will help take his mind off Evi's death.
The officers end up calling Vince and Dave for help as well. They arrive but Dave is reluctant. Mr. Campbell wants to go by himself, but Nathan stops him and splits the group into pairs. Vince goes with Dwight. Vince asks Dwight if he has visited Lizzie's grave. Dwight gets upset, but Vince continues to pry. Dwight says Lizzie would be nine now if she were alive. They hear a screeching noise.
Audrey goes with Mr. Campbell, who asks if she has any tracking experience. Audrey sees a blood trail, but it leads to a gutted raccoon. Nearby, they find a man impaled on a tree. They call the others over and confirm that the man was the killer, and wonder if Rory killed him. Mr. Campbell insists his son is innocent. Dave, over Vince's protests, suggests it was the work of a wendigo, as the area was their hunting ground in the Native American legends. Dwight looks the body over and says it was torn apart by human teeth. Mr. Campbell says that if it was a wendigo, it is not Rory, as the Campbell family does not have a Trouble.
The group separates again. Dave tells Nathan that even if wendigoes aren't real, a Trouble could turn someone into them. They should be careful, wendigoes have incredible speed. They run into a group consisting of Duke, Reverend Driscoll, and Driscoll's followers. Driscoll's followers threaten them with their guns, but Audrey and the others come up and order them to stand down. Driscoll says he and his followers are there to wipe out evil. Mr. Campbell allows them to help, as searching a forest needs as many people they can get.
Nathan goes with Audrey. They wonder if Duke has been swayed to Driscoll's side. Duke goes with Dwight and comments on how Dwight carries a crossbow instead of a gun. Dwight sees a girl in a tutu up ahead, but is distracted by a screech, and the girl is gone when he turns back around.
Nathan and Audrey find a girl's sweater, and hear screeches coming from multiple directions. Rory runs up, claiming that he was the one who killed the killer. One of Driscoll's followers comes up and says that something bit his leg. Rory runs away and they lose track of him.
Everyone regroups and makes camp as night falls. Duke talks with Audrey and tries to assure that he hasn't joined Driscoll's bigoted group, he just wants answers about Evi's death, his father, the circular maze tattoo, and others. She says she can understand that and gives him a tip on how to start his campfire, commenting that she has no memory of learning that, it is just in her head. She warns him to be careful in his search for answers.
More screeching is heard and everyone draws their guns. Mr. Campbell declares he will take the fight to the enemy and charges into the darkness. Driscoll, his men, and Duke follow him. Nathan trips and finds his hand covered with the blood of a gutted deer. A girl named Frankie Benton appears before him and begs for his help. Her sister Sophie appears and Frankie restrains her. Sophie's mouth is dripping with blood and Frankie explains that she is hungry.
Audrey runs into Driscoll, who gives one of his anti-Troubled speeches and declares that he and his group will wipe them all out. She tries to ask him if he has seen Nathan but he walks away.
Nathan grabs Audrey from behind and gags her with his hand so she doesn't cry out. He introduces her to Frankie and Sophie. They explain that their Trouble triggered when their parents were killed in a plane crash, and it grants them incredible strength, speed, and senses, but also an incredible craving for flesh. They can eat any meat, but human flesh is intoxicating. Their middle sister, Amelia, was dating Rory. Nathan figures that Rory lured the killer into the woods for Amelia to eat. Sophie is in pain and Frankie explains that their hunger is terrible and regular food doesn't stop it. Nathan advises them to lay low until morning to avoid Driscoll's followers.
The next morning, Rory meets Amelia in an abandoned ranger station. She's suffering from hunger and warns him to stay away or she may lose control and devour him.
Driscoll tells Duke that he will explain what happened to Duke's father when this adventure is over. Duke is looking forward to that. As Duke walks away, Rory knocks Driscoll out and drags him away without Duke noticing.
Nathan and the others reach the ranger station but Amelia is nowhere to be found. Sophie collapses. Dwight volunteers to to take her to his truck while the others continue to search while avoiding Driscoll's men.
Rory ties Driscoll to a tree and urges Amelia to eat him. She is hesitant, a killer is one thing, but a preacher is another. Rory says it is okay to kill him because he wants to kill all the Troubled people.
As Dwight carries Sophie, he talks about The Nutcracker
and how his daughter Lizzie loved the ballet. Dwight steps on a bear trap and collapses.
Everybody hears Rory screaming for help and moves toward his voice. However, Frankie sniffs the air and tells Nathan and Audrey that he is leading everyone away from Amelia.
Dwight believes he is doomed and offers that Sophie eat him so she can regain her strength and survive. She refuses and urges him not to give up. Inspired, Dwight manages to rip the bear trap's post out of the ground and limps off carrying Sophie with the trap still on his leg.
Amelia draws a knife and Driscoll prepares for the end, but she instead cuts him free. She urges him to run as far as possible while she can still control herself. Instead, he knocks her down and takes her knife. He pins her and holds up the knife. Amelia begs for her life, but Driscoll says the Troubled are all sinners and must be destroyed. Audrey and the others arrive. Frankie charges at super speed, but at the last second, Audrey shoots Driscoll, killing him.
Shocked, Nathan asks Audrey why she didn't aim for his non-vital areas. Duke and Mr. Campbell arrive. Mr. Campbell accuses Audrey of murder, but she says she just saved someone's life. Later, Dwight, his leg in a brace, explains that he was able to save Sophie with a morphine drip. Dwight drives the three sisters to the slaughterhouse, where they can feast to their heart's content until the Troubles are over. Rory and Amelia promise to wait for each other. Dwight's truck has a picture of himself and Lizzie. Lizzie is the girl in the tutu.
Duke is angry about Audrey killing Driscoll, because his biggest lead is now gone. Audrey repeats that she had no choice.