The story opens with a montage of the original movie. We see each kill happen in 3D as it did in the original movie. It also shows the infamous final scene from the original movie with Sally riding away in the back of the pickup truck while Leatherface swings his chainsaw maniacally in the middle of the road.
Next we cut to a police car pulling up in front of the Sawyer house behind another car. Inside the first car is the Carson family (cousins, aunt, uncle to the Sawyers). They run inside and barricade the door and hold up arms along with the Sawyer family. Sheriff Hooper (Thom Barry) arrives outside the Sawyer family house, driving a police car, and he shouts to them that he only wants the boy, Jed a.k.a Leatherface.
He says that the woman (Sally) said that a man with a chainsaw killed all her friends. Drayton Sawyer (Bill Moseley) shouts that they were trying to protect their family. Hooper constantly tells him that he needs to take the boy into custody and that things don't need to get out of hand. Drayton thinks it over after members of the family agree to give up Jed. So Drayton goes into another room and shouts at Jed telling him that he has to go out there and give himself up.
Just then a group of towns people from the town of Newt, Texas, led by Mayor Burt Hartman (Paul Rae) who have come with one thing in mind: to kill the entire family. As Drayton and the family prepare to surrender, Burt and other townspeople begin to attack by setting the house ablaze and shooting through the house.
Pretty much all of the family is killed in the chaos despite Sheriff Hooper's attempts to stop them. We see Loretta Sawyer (Dodie Brown) cradling a baby, attempting to protect it, but one of the bullets flies through the windows and goes through her right shoulder and the baby's.
After the chaos dies down at nighttime and the house is burned down, we see Gavin Miller (David Born) stumble upon a barely alive Loretta who is still holding on to the baby. Gavin takes the baby from her and kills Loretta by kicking her directly in the face. He runs to his wife Arlene (Sue Rock) saying that he found a baby and that they should adopt her. They decide to name the baby Heather.
In the present day, adult Heather Miller (Alexandra Daddario) is working in the meat section of a grocery store. She is interrupted by her friend Nikki (Tania Raymonde) who is super excited about a trip that she, Heather, Heather's boyfriend Ryan (Trey Songz), and Ryan's friend Kenny (Keram Malicki-Sánchez) are taking to New Orleans.
Heather goes home to her grungy looking apartment where Ryan is sparring on a punching bag. We see that Heather has strange pieces of art that include bones and a lot of black paint. Ryan gets her to relax from being stressed about the trip by making out with her. Just as they are about to have sex they are interrupted by a knock at the door. Ryan goes to answer and gets some mail for Heather, which is a will for her. It states that her grandmother is dead and has left a house for her. However, Heather is confused because her grandparents died years ago.
She goes to confront her parents who reveal to her that she was adopted. They warn her not to go to Texas, but she (completely pissed and hurt) leaves and goes back home to Ryan. When she arrives, she tells Ryan she has to go to Texas to learn more about the house and her real family. Ryan doesn't object at all and surprises her when Kenny and Nikki appear, offering to go with them.
So they drive towards Texas and on the way they stop at a gas station and accidentally hit someone walking with the van. It's pouring outside, and the guy introduces himself as Darryl (Shaun Sipos). He says that to forget about them hitting him that they can just drop him off when they get to Texas, and he even offers gas money. So they figure what the hell and let him come along.
When they finally reach the house they are met at the gates by Farnsworth (Richard Riehle) who gives her a keychain full of keys (one huge one in particular) and he also gives her a letter from her deceased grandmother Verna and advises her to read it immediately. He goes on his way, and they go through the gate. The house is stunning and filled with antiques. They explore the house and decide that they should get some food from a local store that may be around.
Darryl offers to stay behind and set all their bags up for them, and he also gives them some money for food. They leave him at the house and go into town. After they leave, Darryl immediately starts stuffing things from inside the house into his bag. (He's obviously a thief/scam artist). He explores through the house and uses the keys to get to every door.
However, he wonders what the large key goes to and goes all throughout the house until finally he stumbles upon a hidden room behind a wall. He goes into the room which leads him to a door. He uses the big key on the door and goes down into a wine cellar of some sort, and when he gets there he sees a bunch of weird items, including a plate with old rotted food sitting outside a large metal door.
He tries to open the metal door various ways, but it doesn't give. As he looks for something to pry it open with, he turns back to the metal door and Leatherface (Dan Yeager) appears and strikes him over the head with a hammer (reminiscent to the scene of Kirk in the original movie). He bashes his head in repeatedly with a hammer on the floor until he is dead.
While in town shopping for things, Heather is approached outside a store by Deputy Carl Hartman (Scott Eastwood), who is clearly attracted to her. Inside the store, we see Nikki flirting with Ryan. Ryan clearly cheated on Heather with Nikki, but blames it on them both being drunk. Nikki claims that he was begging for it. Ryan tells her to stop and forget it happened and walks away, disappointing her.
Back outside, Heather tells Carl where she's staying, and the Mayor (who is Burt Hartman from earlier in the film) overhears this and asks her if she's related to the Sawyers. She lies and says no and quickly leaves with her friends.
When they arrive back at the house, they see that everything is a wreck. They deduce that Darryl must have been a thief and robbed them and left. They relax since it wasn't anything extremely valuable missing and have a few drinks. Kenny (being a chef in training) starts making up some steaks as night falls. Ryan is in the study playing on the pool table, Nikki is outside smoking and eyeing Ryan from the window, and Heather is exploring the house upstairs.
While Kenny is cooking, he notices the wall/door that Darryl went through, and he walks through. He calls out to Ryan, but Ryan has music playing very loud so he can't hear him. Kenny walks down into the cellar and sees Darryl's bag and a pool of blood. He calls out for Darryl, but doesn't get a response.
Then when he steps into the room with the metal door, he sees the metal door is wide open. As he walks through it, he steps into a dark hallway. Suddenly, Leatherface jumps out of the darkness and chases Kenny. Kenny gets halfway up the stairs when Leatherface shoves a hook through his back. He drags him downstairs, and Kenny's screams are drowned out by the loud music.
Nikki runs into the study where Ryan is playing pool. She screams and says there's something crazy he needs to see, and she looks scared. She leads him outside into a barn house in the back. When they get back there, she points to a bucket covering something. When Ryan removes the bucket he sees there is a bottle of alcohol and two glasses there. He turns around and is shocked to see Nikki standing half naked saying "told you it was crazy." She winks at him, and they proceed to have sex.
Back in the house, Heather is upstairs and stumbles into a room where the corpse of Grandma Verna is sitting in a chair, decomposing. She screams and runs downstairs to find everyone, but she sees the house is empty.
When she runs into the kitchen, she sees Leatherface holding a severed hand and cutting the fingers off into a bowl. She screams and catches his attention, and he grabs her and tosses her onto the kitchen floor. She hits her head and is knocked out. When she comes to, she is in a room in the cellar and we see Leatherface cutting up Darryl's body in pieces.
Then we see him hang Kenny's body up on a hook and saw his body in half. Heather quickly jumps up and runs up the stairs. Leatherface chases after close behind. She falls down the front stairs when she gets outside and runs to the back of the house which is a graveyard full of the Sawyer/Carson family. She finds an unfinished grave with a coffin and climbs inside.
As Leatherface stalks the graveyard, he hears Heather crying and jumps on top of the coffin and begins cutting into it. Ryan and Nikki step out of the barn house after hearing the chainsaw and they see Leatherface cutting into something.
They call out to him asking who he is and when he sees them, he stops cutting into the coffin and runs toward them. They quickly run back into the barn house and barricade the door. Ryan finds a shovel and Nikki finds a loaded shotgun. She shoots through the door as Leatherface tries to cut through, she shouts "Welcome to Texas Motherfucker!" Suddenly it gets quiet. They see a pair of lights through the door, and the van suddenly crashes through the barn house; it's Heather.
They quickly jump in and Ryan drives through the barn and towards the front gate. He tries to ram it but to no avail. As Leatherface catches up to them, Ryan backs the car up so the gate can open automatically and they drive through it. Just as they do, Leatherface manages to cut through the front tire and the side of the van. This causes the van to flip over and crash just as they get about 15 feet from him.
Heather looks over, and we see Ryan is dead. (A huge piece of glass from the windshield got lodged deep into his neck). She and Nikki scream as Leatherface tries to cut through the van. He even goes so far as flipping it onto its side. Heather is able to climb out through one of the windows. Leatherface cuts Nikki on the side a little and Heather gets his attention. This distracts him, and he begins to chase Heather through the woods. She manages to reach a fence which leads to a carnival on the other side, and she hops it.
Leatherface doesn't stop, and he cuts through the fence, chasing her through the carnival as people run all over, screaming. She gets to the mini ferris wheel and jumps up and grabs onto one of the seats as it lifts her up. Leatherface waits on the other side as she begins to descend back down. But just as she gets close to him, Officer Carl orders him to freeze. Leatherface tosses his chainsaw at Carl, and he ducks just in time. But this gives Leatherface enough time to escape into the woods.
Carl takes Heather to the police station for questioning. There we see Sheriff Hooper waiting and when she describes Leatherface he is shocked and begins to think Jed must still be alive after all these years. She also admits that she just found she was a Sawyer. Carl pulls a box labeled "Evidence" and sits it on the table saying there is some crazy stuff in it about the Sawyers/Carsons. Hobbs orders Carl to leave and go look for the maniac. The mayor shows up and demands to speak with Hooper, so he leaves Heather alone while he goes to talk to him.
As soon as he leaves, Heather begins to go through the evidence box that Carl pulled, and she sees how her entire family was killed without a fair trial by the townspeople and the mayor and her adoptive mom and dad. She reads about the entire incident that took place that night. Meanwhile, one of the police officers was investigating the crashed van and tells Hooper that no one is here (Nikki and Ryan's body are missing). Hooper orders him to stay at the site, but the officer sees a trail of blood that leads down the road, and he follows it.
The mayor is yelling at Hooper saying that Jed can't be alive because they burned that place to the ground. The officer calls Hooper back and informs him that the blood led back to the house. The mayor orders him on the walkie to follow the blood and the officer does so. When he gets in the house, he turns on a video call so the mayor and Hobbs can see what he sees. As he follows the blood into the cellar and down a dark hallway he comes upon the room where Kenny, Darryl, and Ryan lay dead and butchered.
He sees a freezer and the mayor opens him to order it. As he gets closer and closer the freezer suddenly pops open and Nikki jumps up, screaming. This shocks/scares the officer causing him to shoot Nikki in the head and accidentally kill her. The video call drops and the mayor and Hooper are shocked by what just happened.
The officer runs back up the stairs of the house and is attacked by Leatherface who bludgeons him with an ax and then begins to chop into his back repeatedly. Mayor Burt decides to confront Heather saying she must have something to do with this. As Hooper tries to stop him from going into the room where she was left, they see the evidence from the night the Sawyers were killed sprawled all over the table, and Heather has written the word "Murderers" on one of the sheets.
Back at the house, we see Leatherface crafting a new mask from the face of the police officer he just killed and he sews it onto his own face. Heather is on the streets of the town, and she reaches a payphone and calls Farnsworth. She tells him that she knows everything, and he tells her to meet him at a local bar. When they meet he informs her that he warned her to read the letter immediately because Verna detailed everything she needed to know.
He also informs her that Jed (Leatherface) knows she is still alive, but he doesn't know who she is. Suddenly the mayor arrives and chases her out the bar. She grabs a knife before she runs out and just as she reaches the street, the Mayor's partner, Ollie (Ritchie Montgomery), hits her with his car. He jumps out to grab her, but she quickly slashes his face with the knife and makes a run for it. Heather gets a good distance and then runs into Officer Carl. She asks him to get her to the bar, so she can help Farnsworth and warns him that the Mayor is after her.
She hops in the backseat and Carl drives towards the bar. They see Farnsworth outside, and he sees them, but Carl keeps going. Heather shouts at him and then realizes he's helping the Mayor when the Mayor calls his phone. She also discovers that the Mayor is Carl's father! The Mayor tells Carl over the C.B. radio to bring her to the old slaughterhouse that the Sawyers used to own. Little do they know, though, that Leatherface has a C.B. radio in a truck and overhears this. He grabs his best chainsaw and goes out into the night.
Farnsworth rushes into the police station and warns Hooper that Heather is in trouble and that a police officer took her. Hooper puts a lock on the squad car's location and realizes where they're going. He quickly leaves. When Carl arrives at the slaughterhouse, he goes to tie Heather up from some ropes. When she tries to attack him, he accidentally rips her shirt down the middle, but she stays tied up. He leaves her there and tapes her mouth shut. Outside, we see the Mayor and Ollie have arrived. The Mayor tells Carl to leave and that they'll handle her.
Back inside we see Leatherface is behind Heather and he places his chainsaw on her shoulder. She tries to scream, but they are muffled by the tape. He steps in front of her and revs the chainsaw. As he gets closer and closer to her with it, he stops and notices the bullet scar on her shoulder. (The same scar from when she and her mother Loretta were shot). He removes the tape from her mouth, and she begins to beg and plead with him repeatedly telling him that "It's me! I'm Heather! I'm your cousin! Please let me go."
Leatherface is shocked by this but cuts her free, just as Ollie and the Mayor arrive and begin to beat the crap out of Leatherface. Heather makes a run for it. As soon as she gets outside, she hears Leatherface yelling out in pain as the Mayor and Ollie beat him repeatedly. The Mayor wraps a chain around his neck and tells Ollie to power it on. The chain leads into a giant meat grinder.
Ollie runs to go power it on and just as he does he is attacked by Heather who shoves a pitchfork through his body and kills him. As the chain begins to pull Leatherface closer to the meat grinder, Heather shows up and tosses him his chainsaw. Leatherface uses it to cut the chain and free himself. He rises up, and Heather smirks and tells him "Do your thing cousin."
Leatherface then cuts both of the Mayors ankles with the chainsaw. The mayor falls onto the ground and begins to crawl backwards, unknowingly towards the grinder. Hooper shows up with a gun and sees the chaos. The Mayor constantly yells for him to shoot, but Hooper slowly lowers his gun when he sees Heather shouting for him not to shoot, and he leaves the Mayor to die. The Mayor ends up crawling back into the grinder and is shredded to pieces.
Back at the Sawyer house, we see Leatherface sitting slumped in a chair, and Heather is standing next to him. She tries to touch his face, but he gets up and goes down into the cellar. Heather finally reads Verna's letter which (in flashback) Verna Carson (Marilyn Burns) details that Jed is the only blood relative she has left now and that whether she chooses to stay or not, she should never forget where her home is.
We see Heather go down into the cellar. She stares at Leatherface face to face as she grabs his tray of old food and goes upstairs. She has decided to stay. The movie ends as Leatherface grabs the metal door, and slams it shut. In a post-credits scene, Gavin and Arlene show up at the mansion to see Heather, greedily seeking a share of her assets. As they wait by the door, Leatherface comes out with his chainsaw.