War of Hearts by Samantha Young

Thea Quinn has no idea what she is. All she knows is that her abilities have been a plague upon her life since she was a child. After years of suffering at the hands of a megalomaniac, Thea escaped and has been on the run ever since.

The leadership and protection of his pack are of the utmost importance to Conall MacLennan, Alpha and Chief of Clan MacLennan, the last werewolf pack in Scotland. Which is why watching his sister slowly die of a lycanthropic disease is emotional torture. When Conall is approached by a businessman who offers a cure for his sister in exchange for the use of Conall’s rare tracking ability… Read more.