A Pinch of Magic by Michelle Harrison, published by Simon & Schuster
Living on the isle of Crowstone, surrounded by eerie marshes and a formidable prison, the Widdershins sisters: Betty, Fliss and Charlie, are desperate for adventure. But when Betty strays too far from home, she learns the awful truth: a deadly curse has haunted her family for generations. If Betty and her sisters leave Crowstone, they will be dead by sunrise.
But the knowledge of the family curse comes with a bit of excitement too! Each sister inherits a magical object, been passed down the family: A scruffy carpet bag, a set of wooden nesting dolls and a gilt-framed mirror… none of them are what they seem.
Will they be enough to help the Widdershins break the curse? Or will the sisters have better luck with a mysterious prisoner who claims he can help them?