When journalist and ghost sceptic Will Storr heads to Philadelphia to meet Lou Gentile, a demonologist, he expects a little fun with an amusing eccentric. What he gets are terrifying experiences of spectral lights and horrific demonic growling - and all of his safe, adult preconceptions about ghosts instantly vanish. In the cold light of day, Will decides on a quest for the truth about ghosts. He meets professional paranormal investigators and takes part in seances and a vigil in the most haunted house in Britain, tries out divining rods and ouija boards, and goes on set with TV's Most Haunted. But Will also seeks out the sceptics in clinical psychology and philosophy who ask if spirits are really just in our heads. His journey is full of bizarre, terrifying and hilarious experiences, each one a new insight into life, death and what might come after.