The well of shades - Juliet Marillier

Sent home to Ireland on a secret mission for King Bridei of Fortriu, Faolan must first deliver the news of a brave warrior's death. Unexpectedly, Bridei's chief assassin and spy also finds himself facing the demons of his family's dark past. By the time he tracks down the powerful Christian cleric who may be a threat to Bridei's pagan kingdom, Faolan has become responsible for a child, a dog and Eile, a troubled, volatile young woman.

For Eile, the journey to Fortriu is confronting. Accustomed to a life of deprivation and struggle, she finds herself facing an unfamiliar world, full of new lessons. For her, the hardest challenge of all will be learning to trust.

At Bridei's court in White Hill, disturbing news from the neighbouring kingdom of Circinn prompts the king to call his chieftains to council. But after the disappearance of Bridei's closest adviser and the tragic death of a young maid, the threat posed by the encroaching influence of Christianity appears to be the least of the dangers at hand . . .