A bustling town deep in the frontier at the foot of an endless sea of trees... It is into this wild and untamed setting that a young man collapses, memories gone and only his name to guide him.

Bereft of his past, Adol Christin wanders the town of Casnan searching for clues to his identity. Joined by a man who claims to know him, the young adventurer helps rescue doomed miners from a monster outbreak - an act which attracts the attention of the Romun Army Governor General in town. Impressed with their skills, the pair is enlisted to explore the Great Forest of Celceta and map its vast expanses - a task which many have attempted in the past, but from which none have ever returned alive.

With only his wits to help navigate this strange and uncharted frontier, Adol must brave the perilous forest as he struggles to regain his memories and decide whom he can trust, and who is simply attempting to take advantage of his memory loss in order to deceive him...