An evil mask unleashes demons onto a group of theater goers.
Cheryl is leaving a subway station in Germany when she sees a creepy man wearing an iron mask. The man stops Cheryl and hands her an invitation to the grand reopening of the Metropol at 6 pm that evening. She meets up with her friend Kathy and tells her about the invitation, which she also grabbed one for Kathy. Kathy agrees to skip class in order to go to the theater.
That evening people start to pour into the theater including Frank and Ruth, Hannah and Tommy, George and Ken and Werner and his daughter Liz. Werner walks over to a lobby display which consists of a dirt bike with a driver holding a samurai sword in one hand and a mask in the other. Warner warns Liz not to touch the mask. The mask is grabbed by Rosemary who dons the mask and shows it to Tony and Carmen. As she is taking off the mask Rosemary is cut on her cheek. George and Ken sit down next to Cheryl and Kathy and the film starts. The film consists of a group of four friends who explore the ruins that are supposed to house the tomb of Nostradamus. They find his tomb with a book and a similar mask to the one which Rosemary put on. Jerry dons the mask despite a warning from Bob, who reads the book and tells him those who put on the mask becomes a demon and an instrument of evil. After receiving a cut from the mask, Jerry becomes possessed and murders his friends one by one. Rosemary’s scratch starts to bleed again and she leaves and goes to the lobby restroom. Rosemary stares in horror as her wound starts to pulsate and finally explodes in a puss ball.
Carmen goes to the restroom to look for Rosemary and finds her sitting in a stall transformed into a demon. Carmen runs out of the restroom, but is scratched by Rosemary in the neck. Werner notices Liz is gone and starts calling for her. Carmen stumbles around the theater and ends up at the opposite side of the projection screen as the audience. As Jerry is killing Edith, his last friend, Carmen rips open the projection screen and collapses on the other side. In the balcony, Rosemary uses a curtain rope to strangle Liz and her lover as they are kissing. A crowd gathers around Carmen and she quickly transforms into demonic form. Carmen attacks Frank and rips his throat open. Werner stumbles upon the body of Liz and has his eyes ripped out by Rosemary. The theater crowd panics and tries to escape the building only to find the doors now lead to a stone wall. Tony takes over the situation and tells everyone to find the emergency exits. One woman walks into a storage room and is attacked and killed by Rosemary, who rips the scalp off the woman. George, Ken, Tony and another man push a soda or snack machine against the door of the storage room, confining Rosemary to the room. Tony leads a group to the projection room in the hope that stopping the movie stops the demons. Tommy and Hannah are separated when Hannah panics and stays in the auditorium. The group in the projection room find out the projector is automatic and they begin smashing all the equipment which manages to stop the film. The group of people return to the auditorium from the projector room to find Werner, who tells them the theater holds the power not the move. Tony grabs Liz’ body to throw it over the balcony when Frank turns into a demon and attacks Tony. Tony pulls out a knife and manages to throw Frank over the balcony. Frank lands above Hannah and vomits green goo onto her face. Tony tells everyone to start ripping up the seats to use as a barricade. Liz revives as a demon and bites Tony’s leg, while her lover now as a demon also attacks Tony. Tony and the two demons fall over the balcony and George uses Tony’s knife to cut the rope that was still attached to Liz’ lover.
Tommy and Hannah reunite. Hannah wants to join the others but Tommy thinks they are better on their own. After barricaded the doorways, the group in the auditorium break down a wall and find another room. The follow a series of rooms which lead to nowhere and return to the auditorium. A pair of policemen pull up next to a group lead by Ripper who are in a stolen vehicle and also are carrying cocaine. Ripper and his group, Nina, Hot Dog and Baby Pig, flee from the police and enter the theater when Werner leaves the theater. The cops walk up to Werner who is a demon and he attacks them. Tommy and Hannah try to escape through an air conditioning shaft, however Hannah transforms into a demon and kills Tommy. Ripper’s group remove the machine blocking the door Rosemary is stuck behind and then leave. Nina stays to investigate the room and is killed by the woman who had her scalp removed. Ripper, Hot Dog and Baby Pig hear Nina’s screams and go to help her but are chased by a group of demons. The group in the auditorium hear loud noises and thinking it is a rescue party start to tear down the barricades to the protests of George. Ripper, Hot Dog and Baby Pig are surrounded by a group of demons and they decide to go out fighting with Ripper’s last words being see you in hell. The demons break into the auditorium and attack the patrons. Ruth is killed when Rosemary crushes her head in a theater seat, while Ingrid is grabbed and killed as she is trying to escape.
George, Cheryl, Ken and Kathy are the only ones that make it out of the auditorium. Kathy begins to feel ill and she turns into a demon, forcing Ken to crush her head with an air conditioning vent. A fully formed demon erupts from Kathy’s back and scratches Ken. Ken realizes he is going to turn into a demon and he begs George to kill him with the samurai sword. George initially refuses but cuts off Ken’s head when Ken turns into a demon. George takes the dirt bike from the display and with Cheryl sitting behind him, drives in circles around the theater killing demons with the sword. A helicopter crashes through the roof of the theater opening a large gap in the ceiling. George finds a grappling hook gun and fires it towards the hole in the ceiling. After making it onto the roof George is attacked by the Man in Black but manages to puncture his skull on rebar with the help of Cheryl. George and Cheryl climb down to street level and run across the city as the demons tear the city apart. A family in a jeep heading west picks them up, however Cheryl transforms into a demon and she is shot by Kirk, the son. George and the family continue to head west where the father hopes to start a new life.