The crew hunker down inside the ruins of London's Fort Horsted, which is said to be haunted by demonic spirits.
Zak, Nick & Aaron explore the Hellfire Caves outside London, England, where they recreate past secret pagan rituals and conjure the spirits of 18th-century English royalty, who are said to still roam the catacombs.
Zak, Nick & Aaron explore the Riviera Hotel in Las Vegas, NV, with special guestsMötley Crüe singer Vince Neil and poker champion Jamie Gold, to evoke the spirit of Frank Sinatra in his old penthouse suite.
The crew investigates Gary Galka's house, inventor of the MEL Meter device, to help him find closure after the loss of his daughter.
GAC revisits Linda Vista Hospital in East Los Angeles.
The GAC spend this week's lock down in the Victorian-era National Hotel in Nevada City, Cal.
The guys visit Bisbee, Ariz., to investigate the Oliver House B&B and the Copper Queen Hotel.
UFC fighter Brendan Schaub joins the GAC on an investigation involving an unsolved murder at Denver's historic Peabody-Whitehead Mansion.
The GAC visit the underground Shanghai Tunnels of Portland, Ore., which were reportedly used in the kidnapping of unsuspecting victims who were then sold as slaves to sea captains waiting at the waterfront.