Kenji Miyazawa appears as an anthropomorphic cat. Born into a family running a pawnshop, he bitterly clashed with his father over the ethics of profiting from the poor, viewing the business as exploitative. His younger sister Toshi offered vital emotional support during these conflicts, though her chronic illness caused him profound distress. Childhood flashbacks depict him collecting rocks and sharing future dreams with his friend Kanai Hosaka, including moments inspiring poems like "Telegraph Poles on a Moonlit Night."

Oppressed by familial and societal pressures, he moved to Tokyo in 1923, working at a small publishing house. There, a reunion revealed Kanai's rejection of their shared ideals, intensifying Kenji's isolation. He returned to Hanamaki to care for the ailing Toshi. To soothe her fear of death, he read her his original stories, explaining his creative process rooted in nature—manifesting in hallucinatory visions teeming with birds, bears, and other symbolic imagery.

Teaching at an agricultural school, he employed unconventional methods: instructing students to close their eyes to grasp concepts like temperature and leading outdoor excursions. His poetry collection "Spring and Asura" baffled students, mirroring broader societal incomprehension. Witnessing farmers' harsh labor triggered intense hallucinations of skeletal corpses and trapped spirits, culminating in a physical collapse before his class.

Driven to aid farmers directly, he resigned to work alongside them. Initial efforts met skepticism and ridicule due to his inexperience and privileged background. Undeterred, he labored by day and taught literacy and modern fertilizing techniques by night. His dedication found voice in reciting "Ame ni mo Makezu" ("Be Not Defeated by the Rain") during these struggles. Despite his efforts, some farmers sabotaged his crops, and exhaustion induced further hallucinations. A vision of trains ascending skyward—directly referencing "Night on the Galactic Railroad," inspired by Toshi's death—renewed his resolve. The film concludes with him reaffirming purpose through a segment of "Spring and Asura."

His personality fused fierce idealism with persistent melancholy. He rejected commercial success for his art, declaring he did not write "to sell books," and pursued agricultural reform despite mockery. His creative process translated sensory experiences and emotional turmoil into poetry, visualized through rapidly shifting animation styles blending realism and abstraction. Recurring motifs like trains and snow symbolized loss—particularly Toshi's illness—and transcendence.