Trials of an ARCH Mage: Book 1-Discovery

Jack is a respected young mage of the guild. When war breaks out, he answers the call and along the way discovers a rag-tag street beggar with amazing abilities. This could be a new Archmage, which hasn't happened for a thousand years, but they have to survive long enough to get to the castle of learning where mages are trained before the evil snatches him away.