The Friends - Worlds of the Timestream: The Interregnum, #2

In the decades following the deposition of James IV, High King of Ireland and the worlds he rules, his descendants and relatives continue their struggle to survive clan MacCarthy's genocidal high-tech schemes plots. Katherina Rourke loses everything except her close-knit group of friends when first her mother and then her father are murdered. Sean Reilly, the man she once loved but now hates, and his allies seek to depose a corrupt donal.
Katherina's daughter comes of age as she builds The Friends of the Day dedicated to restoring Tara's true throne. While Katherina's friendships disintegrate around her, a subsequent ruler uses Sean in an attempt to kill Katherina, Jack, and their infant Mara. Will he succeed?