Son of Strength (Sons of Alba #1)
Erin E.M. Hatton

Donnchad has his life plotted out before him, and big footsteps to fill. As the heir of a minor king, he must travel to the High King's court to learn his craft. He's a strong lad, but he will need all the strength of his heart to leave home.
Liosa, the daughter of the late king of Orkney, is an exile in her mother's homeland. Mourning her father and trapped in a course of fate she never wanted, she longs for freedom.
When circumstances push Donnchad and Liosa together, a gentle love begins to bloom. But will they have the strength to see it through?