A young woman who found the phone Bailey Dawson used to record her videos in I'm Haunted 2 begins an investigation into the entity known as Cyr and the strange events occurring around it.
A group of people go on a "serial killer" tour, visiting the sites where legendary deceased murderer Zacharias Cook slaughtered his victims, only to find the killer isn't dead and now has his sights set on them.
The cast and crew of the I'm Haunted movie series discover that the evil entity Cyr from their films is no longer just a character - it has crossed into reality to haunt them for real.