The Tenth Power — Kate Constable

Calwyn was once the most talented chanter in Tremaris, able to command seven powers with a single breath. But a terrible mistake has left her without her magic, just as her beloved Darrow has fallen prey to a sickness sweeping the chanters -- a sickness that seems to have infected the very land itself. Calwyn embarks on a desperate journey across Tremaris to confront an old enemy, heal the dying Darrow, discover the mysterious Tenth Power, and face her own destiny.