In a small village in nineteenth-century Herefordshire the young mistress of the Brobury estate, pregnant for the first time, has strange obsessive dreams which both repel and fascinate her. Ladygrove Manor, the centuries-old home of the Broburys, inspires her with a frenzy of terror for the safety of her unborn child. Her husband, bewildered by her behaviour but half believing in the family curse, turns to the psychic investigators, Dr Caspian and his wife, for help.

Together the Caspians are drawn into the young woman's obsession: the maze in the grounds of the house exerts a powerful attraction over her, but it seems that unseen hands are barring the way when she tries to enter. Meanwhile, her mother-in-law, a half-crazed woman, passes her time in the ruined shrine at the centre of the maze, or attending to her unique and sinister herd of swine.

In this remote part of the English countryside Bronwen and Caspian once more put their telepathic gifts to the test, working their way back through the history of the place to find an explanation of the unseen terrors which continue to haunt its inhabitants. In so doing they unearth the story of an anchoress immured against her will and find themselves in conflict with the destructive forces of an ancient evil.