Diana Wynne Jones Wiki

Annie Hyde is a hereditary witch on the Islands of Blest and the mother of Arianrhod Hyde, one of the protagonists of The Merlin Conspiracy.

Annie is a daughter of Gwyn ap Nudd, a formidable magical individual whom Annie loves but fears.  She has never been able to please him, and so she runs away to marry and afterwards never goes home again.

Annie's husband Daniel Hyde is a weather wizard who travels with The King's Progress.  Daniel manages the weather, while Annie works on the financial end of things.  The two of them are busy, loving but slightly neglectful parents, and when Roddie tries to warn them of the conspiracy, they don't believe her.

They are spirited into captivity, along with the rest of the hereditary wizards of the world, and only the efforts of their daughter and her friends are able to save them, and their world, from the conspiracy.