The South Stack Lighthouse was constructed by Daniel Alexandra and Joseph Nelson in 1808 and lies off the north-west coast of Holy Island near the Isle of Anglesey. It was built to protect ships on the seas between Holyhead, Liverpool and Dublin and the main light can be seen for 30 miles. Before a bridge was built in 1828, the only way to reach the structure was in a basket which was suspended on a rope. The lighthouse has over 400 stone steps down to its footbridge and the areas cliffs host a large number of sea birds. The Victorians encouraged the birds since their cries gave sailors warning of land during foggy weather, in the days before the lighthouse. The treacherous terrain, violent seas and dangerous nature of the job has claimed the lives of a number of lighthouse keepers, mariners and locals. Subsequently, tales of ghostly happenings at the structure are rife. Heavy footsteps have been heard many times on the 400 stairs to the isolated footbridge and uneartly cries and screams have been reported.

David Wells initially reveals a link with 2 Victorian children at the beginning of his walk around who he senses are playing outside. He then links in with a male energy who he says is 'wailing' and crawling on his front up towards the lighthouse. He believes he has a serious head injury and correctly links this event with the name Jack Jones. As the vigils commence David and Yvette are calling out on the lighthouse stairwell where objects appear to be thrown down from above. The team also report hearing moaning sounds, although it is clear from the footage that the winds outside are howling around so this must be considered as the most likely explanation for these noises. Further objects are then thrown as the crew move on throughout the lighthouse, while Stuart suggests that something touches his elbow, and his leg is also pinched by unseen hands. Yvette asks out as to whether the objects being thrown are as a result of the children's energies in the building, and suggests that they throw something at Ciaran - unfortunately no further activity of this sort is captured. As the investigation progresses it appears that a horseshoe is thrown, while David appears to be the focus of much of this supposed Poltergeist activity taking place. Karl reveals that he senses a malevolent entity, and new crew member Geoff is then hit by what appears to be a chicken bone. Karl and Stuart also venture out to the cliff edge where they feel an image which was supposedly seen passing one of the windows has wandered, but no actual image or apparition is captured on film.