Masauji Iwaki governed imperial hunting grounds in 11th century Japan, instilling in his children a duty to protect nature and its animals. When a superior official demanded Masauji's daughter Anju in marriage and Masauji refused, the official retaliated by burning a protected forest and falsely accusing Masauji of the arson. This led to Masauji's imprisonment in Kyoto while awaiting trial.

Following his arrest, authorities ordered Masauji's family – his wife Yashio, children Anju and Zushiou, and their loyal animal companions – to vacate their home and estate. They fled towards Kyoto, intending to prove Masauji's innocence and secure his release. Bandits attacked them during their journey, causing the family to scatter and become separated.

Masauji embodied unwavering integrity and principle, refusing to sacrifice his daughter despite intense political pressure. His sense of responsibility extended beyond duty to ethical guidance for his children, emphasizing humanity and compassion for all beings regardless of status. This perspective sometimes led him to question the rigid samurai hierarchy.

The false accusation and imprisonment directly triggered the family's displacement and suffering, setting the narrative in motion. Though Masauji appears primarily in establishing these events, his influence persists through his children's actions as they endure enslavement and strive for reunion, embodying his legacy of resilience and moral fortitude during their struggles.