There stands a twisted tower... hidden in the Windhome Mountains. Something is imprisoned there -- the Sisterhood of Stars does not know precisely what, but something is bound tight with a wizard's spell so that it can never escape again. Kayl is one of the few to have looked upon the Twisted Tower. She has no desire to see it again -- she left the Sisterhood long ago, settling down to a quiet life. Her sword lies unused in a secret place beneath the stones of her hearth. But something evil is leaking from the Tower. And now a sorceress and a wizard have appeared on Kayl's doorstep demanding she take up the sword again.
This is a good fantasy story that shows a much more dynamic view of the female characters than most sci-fi fantasy. This is part of Wrede's Lyra novel series.