The castoffs

Twenty years ago, mages fought for their survival against the Surrogate, a hive-minded robot army that consumed everything in its path. Now, a trio of apprentice mages must cross the ruined landscape to deliver a magical cure to a remote town. But the would-be heroes aren't exactly of the same mind: Charris is a hotheaded fighter with elemental powers; Trinh is a shy mage who can literally turn invisible; and Ursa is a healer with more power than she lets on. Can our mages stop bickering long enough accomplish their task? And is the Surrogate really defeated?