Poltergeist. The very word conjures up images of satanic demons, vengeful ghosts and mischievous spirits. People have related tales of spirits moving objects and communicating messages for thousands of years. But what exactly is a poltergeist? Is it a ghost, the restless spirit of someone who dies an untimely death? Or is it the manifestation of the psychic energy of a living person? Those who have encountered poltergeists firsthand find the answers elusive and the questions haunting. This provocative episode of A&E's "The Unexplained" offers an intimate look at four poltergeist outbreaks in the United States and England, presenting a wide array of paranormal encounters experienced by people from all walks of life. From a quaint New England Inn to a Kentucky honky tonk, from a remote farm in Oregon to universities in the United Kingdom, "Poltergeist" takes the viewer on a journey around the world and into the minds of people who have seen poltergeists firsthand and those who are trying to uncover the truth behind these mysterious physical manifestations of unknown origin. Poltergeists are actual physical events, and their existence is indisputable. It is the origin and nature of this energy which is in question. Is it possible that we do not yet understand the capabilities of our own untapped energies? As psychics and scientists alike grapple with the mystery of poltergeists, the real answers may lie hidden in the recesses of the minds of those who have met them.