Kiss of the Highlander ~ Karen Marie Moning

This is the fourth book in the Highlander series. Gwen is on a Scotland vacation when circumstances lead her to fall into a cave, where what should she find, but a highlander who appears to be sleeping. The sleeping highlander is Drusten McKelter, who was enchanted, and has been asleep in the cave for 500 years. Now he must figure out exactly how to get back to his time and safe his family and the secrets they guard.