The movie begins in 1988, in Indiana, where we see three best friends, Alexis, Val, and Beverly, on a road trip. The girls are heading to their favorite metal band concert and seem very excited. After driving for a while, they stop at a gas station, where an old store clerk is watching TV.
In the news report, a pastor named John Henry Butler is blaming heavy metal music for turning young people evil. Meanwhile, Beverly takes out a newspaper, and reads about how teens were murdered in recent satanic killings. This spooks her, but Alexis laughs and says it is meant to scare other people, not them.
On the counter, the old clerk advises them to be cautious, saying there’s a lot of evil out there, but Alexis simply says they’re capable of protecting themselves. After fueling up, the girls get back in the car and resume their journey. They turn on the radio, only to learn about three people who were stabbed to death last night, with satanic symbols discovered at the scene.
Moments later, a blue van suddenly passes by, and throws a milkshake at their windshield. The girls quickly pull over to the side of the road and start cursing at the van, but it has already driven away. After a while, they arrive at their destination, and start drinking booze to prepare for the concert.
As they head inside, their attention is drawn to the blue van from earlier. They realize that the culprits must be inside and decide to teach them a lesson. Val then lights a firecracker, and tosses it into the van.
This causes a small explosion, and a trio of guys named Mark, Ivan, and Kovacs emerge. Alexis accuses them of throwing the milkshake at their car, so the guys apologize and offer to make it up to them by giving them some beers. The girls discuss their mutual love of metal music, and then Beverly notices a satanic book in the boys' van, which creeps her out.
Shortly after, the concert begins, and the six of them have a great time drinking and dancing. After the show ends, Ivan says that the night is still young, and invites the girls to a bar, but Alexis points out that there are no bars in this rural area. She mentions that her father is out of town, and invites them to his house, which is not far from their location.
The boys are thrilled by the idea, and accept the invitation. Soon after, the group arrives at the destination, and the boys are amazed by how luxurious the house is. Alexis gives them a tour of the place, and the boys wonder what her father does for a living.
The group then heads to the backyard, where they build a fireplace and sit around while drinking. However, throughout the evening, Beverly seems very tense and worried for some reason. At one point, she heads inside the house to calm herself, and she tells Alexis that she has never done anything like this before.
Alexis assures her that everything will be fine as long as she follows her lead. It turns out Beverly is new to the group, and Alexis says tonight is a big step for her. After this, Beverly decides to go outside again, right when she bumps into Mark and accidentally spills a drink on her clothes.
Mark immediately apologizes to her and offers his coat. When she puts it on, she is shocked to discover a switchblade inside, but Mark quickly explains that it belongs to his brother. This increases Beverly's stress, and she secretly informs Alexis about the switchblade, but the latter advises her to calm down, assuring her that Mark isn’t going to murder them.
Next, the six gather around the fire and toast to a memorable night. Alexis starts a round of a drinking game, Never Have I Ever, and everyone shares stories about interesting experiences they have had. But during the game, Mark suddenly becomes dizzy, and lies down on a patch of grass nearby.
Alexis continues the game, and abruptly declares that she has never drugged anyone's drink. The boys claim they haven’t done this, but to their shock, the girls start drinking from their cups, meaning they have done this. Hearing this, Ivan and Kovacs laugh, asking whom they have drugged, and Alexis shockingly points towards them.
The guys don’t believe it, but are certainly weirded out by the situation. They proceed to leave, but both of them end up getting knocked out as well. Next, the girls drag them inside, and tie them half-naked to chairs in a room.
They then pour water on them to wake them up. The boys are terrified, and as they look around, they notice numerous candles and satanic symbols in the room. They beg the girls to let them go, but Alexis and Val start laughing maniacally, while Beverly stands nervously in the background.
Following this, Alexis reveals that they’re not Satanists, and have no interest in metal music. Instead, they’re actually members of the Daughters of the Dawn, a Christian congregation that commits murders and frames real Satanist cults. Ivan inquires whether they are responsible for the recent killings, but Alexis clarifies that those were carried out by other members of their church, and tonight is their turn.
She further reveals that they orchestrate these killings to look like cult work, so that people will be scared, and convert to Christianity for redemption. Hearing this, an enraged Ivan calls them hypocrites for spreading Christ's word while persecuting people. Alexis tells him to shut up, but Ivan continues to label them as blindly obeying orders without understanding anything.
This enrages Alexis, and she brutally stabs him in the neck, causing him to bleed to death. She then turns to Mark, and forces him to beg for Christ's forgiveness. However, just as she’s about to kill him, Beverly stops her, stating that she needs to discuss something important first.
Val and Alexis are annoyed by the interruption, but they reluctantly follow her out of the room. After they leave, Mark calms Kovacs down, and tells him to reach for his belt nearby, so they can cut the ties with its spikes. Meanwhile, in the restroom, Beverly informs the two girls that she must be the one to kill the two boys.
She explains that she has realized the truth in what the girls taught her, and wishes to complete the task. But then, they notice that the boys have managed to break free and are running away. They immediately rush to stop them, and Alexis even slashes Kovacs’s arm with a knife.
The boys lock themselves inside a pantry, while Val and Alexis frantically begin banging on the door. Alexis says that they’re going to die anyway, and asks them to make it easier for everyone. Meanwhile, Kovacs' arm is bleeding profusely, so Mark tends to his wounds, and ties a band around it.
Outside the pantry, Alexis orders Beverly to get some tools from the shed so that they can break down the door. Alexis blames her for causing the situation, and claims that the blood is also on her hands. An irritated Beverly then walks to the shed, which is only a short distance from the house.
Later, Alexis discovers some aerosol cans in the kitchen, and begins spraying them through the pantry door. This causes the boys to cough and have difficulty breathing. Mark comes up with an idea, and closes the gap in the door with a cloth.
Just then, someone arrives at the house, and it turns out to be Alexis' stepmother, Susan. She explains that she was supposed to go on a trip but forgot her passport. Susan then goes upstairs to her room to retrieve her passport.
Before leaving, she informs the girls that she noticed a blue van outside, and suspected they were being robbed, but they state that they borrowed it from a friend. However, Susan had called the cops, and also notified Alexis's father. The girls are shocked, but Susan asks them to say it was a false alarm when the police arrive.
While leaving, Susan hears noises coming from the pantry, and senses that something is wrong. Alexis informs her that they’re simply having a slumber party. She tries to convince her stepmother to leave, but Susan's curiosity gets the best of her, and she decides to investigate.
As a result, the woman soon comes across a room, where she discovers Ivan's body on the floor. And then this happens… Alexis soon stabs her to death, and Val is horrified as Alexis just killed her stepmom. She begins to panic, especially with the police on their way, but Alexis assures her that everything is fine.
Meanwhile, Beverly is still in the shed when she discovers some papers containing property titles claimed by Alexis' father, as well as a box containing a large sum of cash. Back to the pantry, Mark and Kovacs break wine bottles and decide to attack the girls with them. But before they can do so, Alexis and Val use the aerosol spray to start a fire near the door.
This puts the boys in a more defenseless position, leaving them with no choice but to remain trapped inside. At this point, a sheriff finally arrives at the house in response to Susan’s call. Alexis greets him outside, and claims that her stepmom made the call and it was just a false alarm.
When asked about her stepmom, Alexis says she is sleeping peacefully inside and doesn't want to wake her. She attempts to drive the sheriff away, but he refuses to leave until he meets Susan. He also requests to see her ID to verify that this is her residence.
Panicked, the crazy girl abruptly rushes inside the house, and she hide in a room. The sheriff follows her with his gun, and begins searching the house. He soon comes across the room where the dead bodies of Ivan and Susan are located.
The sheriff then summons the perpetrator to come outside and surrender. Hearing his voice, the boys immediately open the pantry door and seek his help. Mark explains that there are three girls in the house who killed his friend, but the naive sheriff doesn’t believe this and proceeds to arrest them.
But unfortunately… Val shoots the sheriff to death with his own gun. Alexis is shocked to see that Val has just killed a cop. She asks for the gun, but the latter refuses to hand it over, leading to a fight between the two.
Just then, Beverly appears with an electric weed whacker, and points it at them. She orders the girls to stop the murder spree, but Alexis tries to persuade her that they are doing the Lord's work. At this point, Beverly has had enough of all the lies.
She reveals that Alexis' father, who is the cult's leader, has been brainwashing them, while channeling donations into his own accounts. He claims to be helping young and vulnerable people, but in reality, he’s using the money to buy luxurious properties like the one they’re in. Soon after, while Beverly is distracted, Val tries to attack her from behind.
But Beverly also fights back with the whacker, and manages to injure both her friends. At this moment, Mark and Kovacs finally decide to leave the pantry, armed with the broken bottle, but they attack Beverly from behind. Beverly quickly clarifies that she is not with those psychos, and was actually trying to save the boys.
Moreover, she states that those girls are simply being brainwashed. Kovacs is bleeding profusely, and won't survive much longer unless he is taken to the hospital. Seeing this, Beverly reveals that Alexis has the car keys, so Mark decides to go after her, as it is the only way to save his friend.
During this, the lights go out suddenly, so Beverly takes Kovacs to a safe room, and hands him the gun, asking him to stay there. Up next, Beverly grabs the whacker again, and she sets out to find her friends. Not long after, Kovacs notices vehicle lights outside, and realizes that someone has arrived.
He immediately heads outside, and meets Alexis' father, who turns out to be pastor John Henry. Kovacs, who doesn't know his identity, describes the entire situation and begs for his help. John then asks the boy to hand him the gun and then call the cops from his car.
Kovacs naively hands over his weapon, but John doesn't waste a second to shoot him. The evil pastor then enters the dark house, and notices several dead bodies, but doesn’t seem concerned about it. Meanwhile, Beverly discovers the light switch and attempts to turn it on, but Val sneaks up from behind, and tries to kill her.
This leads to a deadly fight between the two, and Beverly tries her best to convince Val that she’s being brainwashed. However, the psycho woman doesn’t understand this, and accuses her of betrayal. Elsewhere, Mark arrives at Alexis’s bedroom, where he finally grabs the car keys.
But before he can leave, she confronts him with a knife, leading to a violent confrontation between them. On the other hand, Beverly is nearly choked to death, but at the last moment, she sets Val's hair on fire. This causes Val to scream in panic, while Beverly takes the opportunity to switch on the light.
After that, she grabs the whacker and enters the living room, where she discovers Kovacs on the verge of death. The boy begs her to save Mark, and ends up passing away. Meanwhile, Mark is strangling Alexis to death, when John arrives and shoots him from behind.
He then scolds his daughter for causing the mess, but Alexis sobs and blames Beverly for the situation. John notes that she was the one who assured him Beverly was prepared for this. Hearing this, Alexis insists she can fix everything, but her father calmly explains that they need to make a sacrifice to get out of the situation.
This confuses the girl, but John explains that he assigned her the mission and chose this house, because it was the only way to clear his name. Suddenly, John begins to choke her, revealing that he had deliberately planned everything. The authorities were suspecting him of the recent killings, so he decided to sacrifice his daughter to gain their trust.
But then, Beverly shows up and knocks him out with her whacker. This makes Alex really happy as her friend came to her rescue. She claims that she’s also a victim, and suggests they should run away together.
When Beverly refuses to believe her anymore, Alexis attacks her again. But during this, Alexis trips on Mark's arm, causing her to fall out the window. Beverly then approaches Mark, who is surprisingly still alive, and helps him get up.
Following this, the two leave the house, and walk towards Alexis’ car. We see Alexis’s body in the ground, while Mark claims he won’t make it, but Beverly assures him that he’ll be fine. To their surprise, after driving for a short distance, they notice Alexis standing in their path, so Beverly does this… The next day, a news report airs on TV about the previous night's events, detailing how six people died due to a supposed satanic outbreak, including Val.
John Henry pretends to be devastated in front of the camera. He claims that his daughter joined a cult, and was responsible for the killings. He asks how many more young people will die in Satan's name, and urges viewers to turn to Christ instead.
Meanwhile, Beverly buys some medical supplies inside the store, and tells the old man not to believe everything he sees on the news. She then returns to the car, and hands the medical supplies to Mark. We also notice that Beverly has stolen John's money, which she found in the shed.
The movie comes to an end as the two finally drive away from the town.