The Will of the Empress by Tamora Pierce

Slowly Daja, Tris, and Briar return to Summersea and Sandry, but they are not the carefree youngsters they were when they left to travel with their teachers. They have things they don't really want to share with the others in their old mental link. Sandry, trying to regain their old closeness, feels rejected and angry: she feels punished. With their refusal to renew their old ties bitter in her mind, she can't believe it when they agree to Duke Vedris's request that they accompany Sandry on a long-overdue visits to the lands and family that Sandry has in Namorn.

The duke is right to worry about Sandry's trip to the north. Empress Berenene of Namorn does not like it that any of the income from the vast Landreg estates has been leaving Namorn to fill Sandry's pockets. She wants that money--and her marriageable young cousin--to stay in Namorn, where Berenene can manipulate both for the enrichment of her throne. Moreover, when she sees how powerful Sandry's three young mage friends are, Berenene decides that she wants them to stay as well. To convince the four young people to stay, the wily, beautiful and http://www.blogger.com/post-edit.g?blogID=7305731425758324430&postID=7142763343701559674powerful empress has an empire full of tricks: great mages who can trap less powerful ones, handsome young men and women devoted to her who will court whoever she orders them to, tax laws to beggar people who look to Sandry for help, family ties like Sandry's cousin Ambros and his family, greenhouses and gardens beautiful enough to enchant even the most hard-hearted of garden mages. She is willing to offer Briar, Tris, and Daja money and power to serve her. She is intelligent, and she has a will of steel.

What can four eighteen-year-olds do against her? It is not as if they are even strong at this point: Tris is besieged by visions, Sandry by lovers, Daja by love, Briar by horrific dreams from the last two years. They have people to look after, a madman, and Sandry's new maid and her children. How can they possibly defy imperial Berenene and her powerful servants?