Kate, her father and little brother, five-year-old Thomas, live in an impoverished state in a grand old house that has been in the family for generations. When her struggling artist father decides he needs to go away and paint, he leaves Kate and Thomas in the care of Mrs Beer - who comes in daily to cook - and her husband, who looks after the garden. In the great old house, with only Thomas (who for some reason has never learned to talk) for company, Kate is terribly alone. So when Aunt Rhoda appears in the quiet village and introduces herself as a relative, Kate is more than happy to welcome her in. But too soon Kate begins to feel the menacing usurpation of Aunt Rhoda's presence, and senses the arrival of the great dog Moon Eyes. She has opened her home to something much greater. a diabolical force of extraordinary malevolence. So begins a deadly struggle for possession - with Thomas as the prize.