It is 1922 and Dr. Alan Twist, an authority in the occult sciences and the paranormal, has been invited by the lord of Cranston Manor in a remote corner of Cornwall to investigate a series of hauntings. His journey is interrupted by the shrill cries of a young woman. Everyone in the region believes that it is cursed by a siren, who emits Banshee calls. If they are heard by two out of a group of individuals but not the third, then that...