S1, E1: In the chilling premiere episode, the team heads to England to unlock the mysteries behind the grisly 800-year history of Chillingham Castle, widely regarded as the most haunted castle in England. At one time, its dungeons were used as brutal torture chambers that took the lives of countless victims, giving way to a myriad of paranormal claims over the years. The Ghost Hunters International team will sort through these many paranormal accounts and determine what tortured souls still linger at the infamous fortress. From there, the team embarks on a terrifying investigation into the abandoned depths of Mary King's Close in Scotland. This underground phenomenon, a warren of vaults and tunnels, was once teeming with destitute inhabitants at the turn of the 19th century. Now, Mary King's Close is considered one of Scotland's most haunted locales.