Emma Dickson has a successful City career and a flourishing relationship. So why does the advertisement for sale of Liza's Cottage, a house she remembers from childhood holidays on the rural Essex coast, turn her well-ordered life upside down with longing?

Mike Sinclair is the new rector of Manningtree and Mistley, the tightly knit community where Liza's Cottage is situated. He is fascinated by the history of the parish, especially the seventeenth century, when Witchfinder General Matthew Hopkins conducted his terrible work. It is his ghost that haunts the old shop in the high street, they say – or perhaps the spirits of his victims.

Emma pins her dreams on her move to Mistley. But, once there, she is haunted by nightmares, dreams of the past, of the cottage's original owner at the time of the witch-hunt. The home she wanted so desperately now seems menacing.

Mike is worried by the increasing level of supernatural disturbance in his parish. What has led to the growing sense of unease and violence that has the town in its grip? He starts to investigate but realises with horror that he himself feels the influence of whatever evil is stalking the town...

As the ancient feast of Halloween approaches, the escalating sense of menace threatens to explode into terrifying violence. Only a handful of people glimpse what is really going on. Can they work out how to defeat the evil before it destroys them all?