The film opens with Justine Fielding (Tuppence Middleton) being escorted out of school by the police, as other pupils look on. It then has a flashback to 5 days earlier, where Justine is reading at the funeral of Darren Mullett (Calvin Dean). She starts to talk about him, when Jason Banks (Olly Alexander) stands up in church and calls her a hypocrite because she didn't really know him. He is then thrown out of church by the sadistic PE teacher.Later on, Justine is talking to her friend Helena (Mary Nighy) about staying in and watching a Keira Knightley DVD, when Alexis (Dimitri Leonidas) decides to invite her to a party his friends Bradley (Alex Pettyfer), Tasha (April Pearson), Kally (Larissa Wilson), Sophie (Georgia King), and Marcus (Tom Hopper) are having. She decides to go to the party, rather than staying in with Helena.At the party, Justine arrives and Tasha tells Jez, the DJ to say something about her appearance. He begins to rap about her, when Alexis tells him to stop, and he is thrown out of the party by Bradley. Later, Alexis and Justine go somewhere quiet, and he tells her they are on a date, at which point they kiss. Bradley, Tasha, Kally, Marcus and Sophie all receive horrible text messages from Mullett's number. During this, someone puts on a clown costume and grabs a chainsaw, before heading up to the room where they are kissing. The figure is revealed to be Bradley, who is playing a prank on them.Jez goes to the cemetery to celebrate Mullett's death, and urinates on his grave, but is killed by an unseen figure, who stabs him with a cross. Later, the group have a toast to Mullett's life, and Justine reveals that she can't even remember who he is.The next day, they arrive at school, and the headmaster mentions that Jez never came home the night before. Bradley threatens another pupil about removing a website he had put up about him. Justine is persuaded to hang around with the cool gang, and tells Helena that she won't be able to make it to her Keira Knightley DVD evening. She finds a teddy bear (stolen from Mullett's grave) in her locker and assumes it is from Alexis. He asks her on another date after this, which she agrees to. She goes to see Jason and he tells her that Mullett was in love with her, and hands her his suicide note. While she is reading the note, a teacher tells her that she will make a great pupil at Oxford university.The pupil threatened by Bradley is then attacked, and sees Mullett's ghost, but is listening to music through headphones, and the loud music sends him deaf.Over the course of the day, the gang get more messages, and Bradley believes Jason is sending them. Jason, meanwhile is in art class, and the teacher tells everyone that the guillotine is faulty and they shouldn't touch it. A boy sent by Bradley fetches him out of class, and then Bradley and Marcus chase him into the gym, where they give him a wedgie, but are interrupted by another message, meaning Jason cannot have sent it. The sadistic PE teacher then arrives and gives Jason detention. The girls decide that Helena has been sending the messages and attack her. Sophie tells Justine that she should sleep with Alexis that night, but goes back into the swimming pool, where she is attacked by Mullett's ghost and drowns.Later that night, Justine and Alexis sleep together, but are seen by Mullett, who tears the badge from her uniform, and re-arranges her fridge magnets, calling her a slut. She returns to school and shows Alexis the suicide note, but his friends tell her she cannot hand it into the police, because she would implicate herself in his death.Marcus is then in PE class, where he sees Mullett's ghost, and the teacher tells him to go and have a shower, just as the art teacher arrives and tells the head that they have found Sophie's body. In the shower, he is whipped with a towel by the ghost of Mullett. He manages to fight him off and heads outside, running into Helena, who accuses him of trying to rape her because he is semi naked. He manages to get outside, and is impaled upon a fence by the ghost.Later on, the gang are at Bradley's house, and they have an argument, where Tasha and Justine get into a fight, and Justine is thrown into the swimming pool. Bradley decides to go and dig Mullett's body up at the cemetery.While he is there, Tasha gets drunk in his car, and invites him to have sex with her. During the act, Mullett appears and pulls him out of the car, and kills him. Tasha runs away, but falls into an open grave, where she lies to Mullett that she fancied him, causing him to decapitate her with a shovel.Justine goes home, and demands that Alexis shows her the site, where it is revealed that he is one of the bullies, and that she was rude to Mullett because he interrupted a conversation about her going to Oxford. She tells Alexis that he is deceitful and a liar, and that their relationship is over.The next day, she arrives at the art class, where Jason painted Munch's "The Scream" painting, and tells him that she was responsible for Mullett's death. He tells her that it has been his fault, because he was scared of being bullied, so he told Bradley that Mullett fancied her. She leaves the room, and Mullett appears, and kills him by jamming two pencils up his nose and slamming his head against the table.Justine approaches Helena and tells her that she is sorry, that her friends, including Alexis were all horrible. Kally runs over and asks her where Tasha is, but Justine tells her she doesn't care. Kally then gets a text message from Tasha telling her to meet her in the art room.Before Justine can follow, she is confronted by Alexis, who tells her he is going to kill Mullett for what he has done to everyone. Justine tells him that Kally is in danger. Kally gets to the art room, and sees "The Scream" with her name on it, at which point Mullett puts a bag over her head, before using the guillotine to slice her hands off. She tries to call the headteacher, but he is too busy with the police, who tell him that Justine's badge has been found near the bodies of Bradley and Tasha.They get to the art room, and find Jason's and Kally's bodies, but are attacked by Mullett. They break free, by stabbing him in the stomach with a screwdriver and head to the common room, where Mullett follows them. Alexis tries to stop him, but is stabbed in the hand with the screwdriver. Justine gets him to stop, but he begins to choke her to death. She grabs his inhaler and throws it across the room, telling Alexis to smash it. He does, and the ghost begins to die.Justine tells Alexis to leave, but he punches Mullett, knocking a sofa over, and finding Mullett's other inhaler, which Mullett then uses. Mullett then stabs Alexis in the throat with the screwdriver. As Justine cradles his body, she looks up at Mullett, disgusted and says "You know what, they were right, you do look like fucking Shrek!", just as the police arrive. Justine is then led out and into the police car seen earlier, having been arrested for the murders. She sees Mullett's ghost but then it disappears.During the credits, there is a sequence where the PE teacher is telling students off, and Mullett is shown getting ready for revenge on him.
Output: Question: Who is arrested for the the murders?, Answer: Justine