Cristian and his sister, July, travel from Madrid to El Garraf with their parents and their little brother to spend the Holy Week in their old vacation home. They learn the legend of Melinda, a girl wearing a red dress that got lost in the labyrinth near the house, who helps people that also get lost in the spot. Carlos, a visiting family friend, tells the siblings that there are different, more sinister versions of the legend. July and Cristian use two hand-held cameras to explore the labyrinth and investigate the mystery of Melinda, until something horrible happens.

Lance Preston and the crew of "Grave Encounters", a ghost-hunting reality television show, are shooting an episode inside the abandoned Collingwood Psychiatric Hospital, where unexplained phenomena has been reported for years. All in the name of good television, they voluntarily lock themselves inside the building for the night and begin a paranormal investigation, capturing everything on camera. They quickly realize that the building is more than just haunted - it is alive - and it has no intention of ever letting them leave. They find themselves lost in a labyrinth maze of endless hallways and corridors, terrorized by the ghosts of the former patients. They soon begin to question their own sanity, slipping deeper and deeper into the depths of madness, ultimately discovering the truth behind the hospital's dark past...and taping what turns out to be their final episode.