There are things that happen in the world that cannot be explained. However much we understand about science and the workings of the universe, some experiences have no rational explanation: phenomena that can't be categorised, events that defy all logic.One of these chilling, strange incidents unfolded in north Wales over several years from the late 1990s to the early 2000s. It is a case that has fascinated everyone who encounters it; a mystery that refuses to unravel.Paranormal follows a present-day investigation into this case. The series follows on the shoulder of Radio 1 DJ Sian Eleri, who was born and raised in north Wales, as she unpicks the threads of the story. Along the way, Sian will encounter experts and eye-witnesses - from exorcists to psychologists, scientists to paranormal researchers - who offer a range of explanations for what happened.