In 1986 Scotland, Angela and Jackson are American siblings who, with a small team of paranormal investigators, run a fake medium scam on clients who believe their houses are haunted. The team uses the reputation of the siblings' late mother to promote Angela's powers as a medium. Jackson orchestrates the scams because of a debt he owes to loan sharks.

During their latest assignment, strange incidents occur, causing Angela to worry about the parallels to her mother, who heard voices and wound up committing suicide because she saw people who weren't there. A new client, Mrs. Greene, requests they come to stop the girls' "screaming."