Paranormal Activity is a documentary-styled horror film centering around a young, California couple named Katie (Katie Featherston) and Micah (Micah Sloat), and a terrifying entity that has been haunting them. In an attempt to capture some of the paranormal phenomenon going on, primarily in their bedroom, Micah invests in a video camera. Most of the activity occurs when the couple are sleeping and it seems to get worse as the nights go on. Micah finds the haunting to be "cool", while Katie is petrified. While Micah taunts the demonic presence, he unwittingly seems to invite the entity in, allowing it to get closer and closer to Katie, whom the demon has been fixated on since she was eight years old.