Little Walsingham has always been famous for religious visions, so when Ruth's druid friend Cathbad, now living with police officer Judy, sees a vision of the Virgin Mary, no one is too shocked. But then a woman dressed in a blue cloak is found dead, and people begin to see the apparition in a different light. The woman is identified as a patient in a local psychiatric hospital. DCI Nelson investigates and finds that staff and patients in the small, privately run hospital seem reluctant to speak to him. Then Ruth, digging in the hospital grounds for a TV programme, makes a chilling discovery - the body of a woman wrapped in a blue cloth. The hospital is run by an order of nuns. Ruth asks Father Hennessey for help, but even he seems reluctant to become involved. As Easter approaches, a great event is planned in Little Walsingham - the re-enactment of the Crucifixion. But preparations come to a halt when another body is discovered - in the church itself. Is someone planning their own re-enactment of the more gruesome events in the Bible? Ruth - who is allergic to religion - seems to have found herself involved in a grisly mystery play ...