Sharon Shinn 
Summers at Castle Auburn [EPUB ebook] 

She was a girl with a talent for witchcraft and a taste for adventure.The illegitimate child of a royal lord, she longed for a man who could never be hers. And she lived for her summers at Castle Auburn.She is a woman who has grown accustomed to standing alone.What she once loved, she has lost. Where she once saw joy, she now sees terrible injustice. And at the castle where she only lived in peace she now walks in fear for her life.