There is an unnerving breakthrough in Sian's investigation into a woman who claimed to summon spirits of the dead when she finds an audio recording of a Helen Duncan seance. Not only is a gravelly male "spirit" heard to speak, but the people gathered comment that they see and recognise him. How is this possible? Sian tests out different theories - was it someone else speaking? Helen putting on voices? Did she have accomplices? How does that explain someone recognising a dead relative? Searching for answers and hoping to understand how Helen was convincing people they were communicating with their dead loved ones, Sian tracks down a modern-day medium. He claims to commune with the other side, but a seance in Edinburgh leaves Sian with more questions than she first started with. And Helen's claims to be able to manifest the physical dead also take things to another level to what she has just experienced. Meanwhile, the investigation takes another turn. Sian reads about spirits supposedly conversing in foreign languages with sitters from different countries. Helen was a working-class medium brought up in Scotland in the early 1900s, but where could she have learned to speak in multiple foreign languages? Sian focuses on evidence posed by Helen's doubters - can they explain how Helen is deceiving her sitters? This inquiry leads Sian down a dark investigative path. Reports of Helen's extraordinary supernatural powers attracted the attention of the scientific community. Helen, determined to prove herself, subjected herself to invasive human testing by the leading psychic researchers of the day. Sian tracks down the leading authority on these human tests, Professor Richard Wiseman, who shows Sian what appears to be photographic evidence of Helen's fraudulent methods. It feels like game over, but why would former lawyer Graham Hewitt want to defend someone who has been publicly denounced as a fraud? Graham points Sian towards a surviving granddaughter of Helen's, who lives in America and says she has "proof" that the authorities feared Helen's abilities because they knew she was genuine.