Domnall by Hazel Hunter

A highlander from the ancient past, a woman from the present day, and a torrid déjà vu.
Jenna Cameron has sacrificed much for her career as an architect, particularly when it comes to love. But when the collapse of a building sends her back to 14th century Scotland, the brawny highlander who finds her changes all that—almost in an instant.
Domnall Mag Raith can scarce believe Jenna’s sudden appearance in the enchanted forest. He and his band of brothers once landed there in exactly the same way. Not only does the lass bear the same baffling tattoos as he and his men, but a powerful attraction binds him to her for reasons he cannot comprehend.
But as Jenna and Domnall search for any clue that could help, one of the oldest and grimmest of all Celtic legends is about to find them.