The Well of Shades — Juliet Marillier

Past sins can break a man, but they can also help him find his way to the truth. And love can sometimes offer a chance at redemption...

Five years have passed since young king Bridei ascended the throne of Fortriu, and he is determined to finally drive the Gaelic invaders from his lands.

King Bridei's dream of uniting his kingdom is almost within his grasp, but there are forces working to destroy him. He sends Faolan, his most trusted advisor (who is by trade also a master assassin and spy), on a mission to ferret out the truth of who is friend and who is foe.

The enigmatic Faolan must return to his homeland, the green isle Erin, a place that holds only pain and sorrow for him. There he finds the lovely young woman Eile, whose beauty shines forth despite her tragic circumstances.

Faolan is forced to confront his past and a family that thought him long dead. He will uncover many truths that challenge everything he believes in ... and, in a cruel twist of fate, these truths may be the key to making Bridei's dream a reality.