Olly and Beverley set their hearts on moving home from Becclesfield to an island just outside the small village of Paganton. There is an historic bridge spanning over a wide river. They soon discover there is much more history to the island than they had known before they moved into one of just six of the homes on the island. Beverley is quickly consumed by the other neighbours and initiated into the "Order". Olly slowly becomes aware of the cult and of his wife's involvement. He follows her to one of the sacrificial ceremonies, where members of the "Order" (all residents of the island) are chanting and dancing naked around an old oak tree next the bridge. The High Priest has in his possession The Book of Shadows which contains, spells, rituals, ingredients and a long historical diary of past events. This book gives him the ultimate power over the other members of the cult.
The book dates back centuries to when six women were tried and then hanged from the bridge for being witches. However, the last one to be hanged managed to curse all of the males on the island. Each fifty years there are special ceremonies of sacrifices but on the 500th year there has to be a male human sacrifice. Olly discovers he has been chosen to be the sacrifice on the 6th June as it will be 500 years to the day when the six witches were hanged upon the bridge.
He knows his wife has been drugging him and has important information from Katie, an outcast living on the island. Together they go in search of The Book of Shadows.
There is a race against time as they discover a number of underground tunnels but he needs to find The Book of Shadows to stop the "Order" and to prevent his own murder.