In the Celtic twilight of ancient Ireland, Sorcha, seventh child of a seventh son, lives with her six beloved brothers and their father, Lord Colum, protected from foreign raiders in the remote and closely-guarded keep of Sevenwaters But now there is an invader inside the keep the Lady Oonagh, a sorceress as fair as day, but with a heart as black as night Though she captivates Lord Colum, she cannot enchant the wary Sorcha Frustrated in her attempts to destroy the family, Oonagh binds the brothers with a spell that only Sorcha can lift If she fails, they will die