Chirin, a newborn lamb, and his mother live a peaceful life in a meadow. As long as they stay inside the fence that protects them and the rest of the flock, they are free to frolic and graze on the delicious clover leaves. However, their idyllic life is shattered when a wolf named Wor attacks them in the dead of night, killing Chirin's mother.

Struggling to process his mother's death, Chirin swears to become a wolf himself in order to avenge his mother, unaware of what this transformation would cost him.