After the happiest summer he could remember, Jack is suddenly summoned to heal the Jarl of Cork, an important ally of the king. If Jack can't find a way to help him, war would consume all southern Ireland. But Jack is reluctant to get involved because he doesn't know what is causing the illness. And worse-much worse-the Jarl is a Dane, just like the ones Jack's father had fought against for so long. Will Jack help an enemy to help his country? Will he listen to the Jarl's plea?