At an exclusive girls' boarding school, a sixteen-year-old girl records her most intimate thoughts in a diary.

The object of her obsession is her room-mate, Lucy Blake, and Lucy's friendship with their new and disturbing classmate.

Ernessa is a mysterious presence with pale skin and hypnotic eyes.

Around her swirl dark secrets and a series of ominous disasters.

As fear spreads through the school, fantasy and reality mingle into a waking nightmare of gothic menace, fuelled by the lusts and fears of adolescence. And at the centre of the diary is the question that haunts all who read it: Is Ernessa really a vampire? Or is the narrator trapped in her own fevered imagination?