The Unbreakable Spell

Oppressed and trodden on by her aunt and uncle, the Duke and Duchess of Bruntwick, who despise her because her father died in debt and her mother was French, Rocana Brunt yearns to escape the confines of their Bruntwick Castle.
Yet when her dear cousin Lady Caroline is ordered much against her will to marry the imperious Marquis of Quorn, simply to extricate him from a potential scandal over one of his many liaisons, loyal Rocana agrees to take her cousin's place at the altar so that Lady Caroline may elope with her beloved Patrick.
At least she believes that this deception and the loveless marriage that would undoubtedly follow, might free then her from her virtual slavery.
Her deceit is not revealed until long after the wedding, when she and the Marquis reach Paris and her cousin and Patrick are safely and ecstatically wed.
And soon, through her own magic and some dangerous escapades, Rocana herself feels a glimmer of hope that she too is about to find eternal happiness in a true love of her own.