In a mythological Scotland, Agatha and Jaime and their new friend Sigrid must try to defeat a newly-released danger to Skye and stop Ingland's alliance with a dangerous enemy.
Agatha and Jaime have rescued their clan and returned home to Skye as heroes. But when Agatha uncovers a threat to their people, she unwittingly releases a terrible power that could kill every living thing on the island. Jaime must race to Scotia to hunt an ancient blood magic, which may be their only chance of survival.
Meanwhile, Sigrid, a Norvegian girl with an unusual gift, journeys to the court of Ingland where a dangerous alliance is forming - one that will soon turn its vengeful eyes to Skye. Sigrid will have to risk everything if she and the people of Skye are to survive the gathering shadows...