REC revolves around a television reporter, Ángela Vidal, and her cameraman, Pablo, who cover the night shift in one of Barcelona's local fire stations for the fictional documentary television series Mientras usted duerme ("While you sleep"). The firehouse receives a call from an apartment building about a woman who is trapped in her house.
When they arrive, the Barcelona police break down the door, with Ángela and Pablo recording their actions. The woman becomes extraordinarily aggressive and bites one of the policemen on the neck. Meanwhile, the terrified residents gather in the entrance hall, and look on as the police and military seal off the building.
The camera crew remains trapped inside the building with the residents, and continues recording in spite of police pressure not to.