A Touch of Evil by Steven L. Smithen

After the debacle in Japan with Paul and the Brotherhood at the hands of her cursed son, Morrigan retreats to her castle on the tiny island An Tra off the coast of Ireland. After licking her wounds a new scheme begins to take root and she marvels in the joy of its simplicity and how one enemy will help her willingly.
Acting swiftly, Morrigan reaches out to her sisters and network of witch circles to be on the lookout for her son, Caleb, and his friends. Even calling up centuries-old assassins to aid her in the cause.
Now Caleb, and Kiera along with their friends Kala, Cameron, and their Mates race across Europe in the hope to put an end to Morrigan’s schemes.
Along the way, Caleb and his friends meet new allies and enemies. From Cameron and Fianna returning to the place where his grandparents met to Kala and Tristan reclaiming a family’s lost honor.
Finally, Caleb comes face to face with his mother and her new forces.
Can the son of a Fallen defeat the Goddess of Death?