Anathema — Rachel Deering

How far will one woman go for the salvation of her beloved? Mercy Barlowe's love for Sarah brings down Hell when her puritanical father discovers them together â€" and has his own daughter burnt at the stake.
 
But death is not the end. A monstrous cult of shapeshifters steal Sarah's soul as part of its twisted plans to resurrect an ancient evil.
 
To defeat them, Mercy must take on a new form that will give her the power and fury needed to defeat the cult. She must become a werewolf!