The Guardian - Shadowstone Legend, #1

The past and present meet, a lover's secret is revealed, and doors to forbidden places open as the Shadowstone's power awakens. Cailen is thrust in to the mystical role of guardian by an ancient pledge. Sworn to protect the bearer of the enigmatic Shadowstone, he must unravel the magic and power of the sacred Fae object before the Fae can reclaim the stone and the one who bears it. Rebecca never believed in the Fae or Faerie legends, let alone considered she was descended from one.
On the hunt for her missing mother, she becomes embroiled in a dangerous quest with an invisible foe and has no choice but to rely on the assistance of the cocky Scottish laird to stay alive. As the talisman's secrets are revealed and passion ignites, Cailen and Rebecca must confront the looming heartache threatening their future.