A chance encounter with a stranger, Priscilla Blunt, seems to offer Nina Crowther an escape from her problems. Middle-aged, struggling to recover from the shock of her husband divorcing her to marry a younger (and pregnant) woman, Nina happily falls in with Priscilla's idea to house-sit for her while she and her husband visit South Africa.
When the phone rings on her first night in the Blunts' Berkshire manor house she expects it to be one of her daughters, but when she lifts the receiver no one speaks. All Nina hears is a shuddering sigh. As the calls persist Nina fears she has attracted an unwelcome suitor - or is it the man who is brutally murdering women in a nearby village? Or could it be one and the same person?