A high-end apartment complex is the setting for demonic disaster in this like-minded splatter sequel to the 1986 cult hit Demons. A spoiled young woman named Sally (Coralina Cataldi Tassoni) is hosting her own birthday party in her apartment. Other characters in the building include a man (David Knight) and his pregnant wife (Nancy Brilli), a little boy who is alone for the evening, and a gym full of workout maniacs. In each apartment, televisions are all tuned to a horror film in which a group of young people find evidence of demons which precedes their becoming possessed. Upset that an ex-boyfriend is coming to her party, Sally goes into her room and turns on the film. A demon bursts through her television. Moments later, the possessed Sally enters the party and slaughters all of her guests, turning them into demons. The possession spreads throughout the building as tenant after tenant is transformed, leading to a furious battle between the exercise fanatics and a pack of demons. The young husband manages to stay alive and makes a desperate attempt to save his wife -- who is being tormented by the now-possessed little boy. He rescues her after the demon child gives "birth" to a Gremlins-style demon and the couple make a dangerous attempt to rappel down the outside of the tower with the raving, drooling Sally in hot pursuit.