The Seventeenth Stair (by Barbara Paul) — Rosalind Laker

After spending most of her life at the Seminary for Daughters of Gentlefolk in Kent, Rosella Eastwood, at the age of seventeen, was now to enter a new world. She was to meet her guardian, Andre Cadel, in Paris and from there - a new life. Rosella could never have imagined the turn her life would take. She was surrounded by the de Louismonts, the family who resented her very existence. Her home, although a charming chateau in the Loire valley, was a house of hidden rooms, of eerie sounds and of mysterious accidents.