The plots of "Paranormal Activity" generally feature ordinary people haunted by unseen entities, such as ghosts and spirits. The protagonists attempt to put a stop to their torment, with often disastrous results.
The first "Paranormal Activity" movie, released in 2009, featured a couple moving into a suburban home and being haunted by a demonic presence. In an attempt to catch the spirit tormenting them, the couple set video cameras up around the house, with this footage providing the basis for the movie. The end of the film reveals that the wife was possessed by the creature, and she killed her husband before disappearing.
As of Dec. 22, 2015, there have been five sequels, including "Paranormal Activity 2" and "Paranormal Activity 3." The sequels feature plots fairly similar to the original film, with a group of ordinary people haunted by a spirit they don't understand, and culminating in the deaths of lead characters. Differences have occurred in spin-offs of the series, such as "Paranormal Activity: The Marked Ones," which features a more traditional horror story with high school students interacting with a mysterious cult. The final film in the series, "Paranormal Activity: The Ghost Dimension," concludes the story, and the setting is once again a suburban house.