Beneath the azure sky of the French Riviera, Christina Mordant looks and behaves like any other attractive girl. But each night as darkness falls, the demon within her betrays its presence.

A thousand miles away, deep in the Essex marshes, a priest of Satan is about to achieve his life's ambition: Canon Copely-Syle of Bentford Priory prepares for the virgin sacrifice which will give breath to the foul abomination he has created...