Moongather — Jo Clayton

Serroi had been an outcast. She was a misborn of the windrunners, of small stature with pale olive skin and certain strangely heightened sensitivities. But now she was a meie--a woman warrior trained by an exclusive order. She had been with her shieldmate at the Plaz when she overheard the assassination plot against the Domnor. A murder was to take place at Moongather--that time of increased access to the demon world.

But while trying to escape with the information, Serroi broke a shieldmate oath, a breach of honor which made life unbearable for her, and forced her back--to search for her betrayed shieldmate and warn the Domnor, although the land itself seemed to be hunting her!