This fantasy epic takes place in the world of Anu: a vast, Celtic-inspired land of magic, mystery, and fantastical history. Yonder's narrative primarily focuses on the adventures of Elaine, a runaway princess; Bran, a young, aspiring adventurer; Fin-Fin, Bran's fuzzy compatriot; and their eccentric wizard mentor, Derfel as they journey north to a long-abandoned province of the Walsh Empire. But the lands ahead are treacherous for the inexperienced. Along the way, Bran and Elaine will encounter a myriad of wonders and dangers alike, all the while being taught by Derfel in everything arcane, for magic is the key to their survival.