The Fionn mac Cumhal Series - Book 2: Traitor of Dún Baoiscne:

Ireland: 198 A.D. Six years have passed since the brutal attack on the community of Ráth Bládhma. The isolated valley of Glenn Ceoch is at peace once more but those who survived still bear the scars of that struggle.

Now, new dangers threaten the settlement.

The warrior Liath Luachra has discovered troubling signs of strangers in the surrounding wilderness. Disgraced druid Bodhmhall fears a fresh attempt to abduct her talented nephew. A summons from the fortress Dún Baoiscne sets them both on a perilous traverse of the...