Roma Kamogawa, sole heir to a Kanto-region farming family, spends his days tending fields in an isolated rural town. His existence follows a monotonous rhythm of agricultural labor, punctuated only by his steadfast friendship with Hokuto "Toto" Mitarai—a bond forged in middle school against a backdrop of peer rejection. Together, they establish the "Don Glees" as a refuge from social isolation.

When Toto leaves for Tokyo’s academic opportunities, Roma continues his routine at a local agricultural high school, his world constrained by bicycle paths and familiar horizons. The arrival of Shizuku "Drop" Sakuma—a spirited outsider with unorthodox perspectives—reinvigorates the Don Glees, transforming it into a trio. Their fragile equilibrium shatters when a forest fire falsely implicates them, triggering a mountain expedition to recover a drone holding proof of their innocence.

Amidst treacherous terrain, Roma confronts his parochial worldview. Natural hazards and interpersonal fractures with Toto lay bare his unresolved tensions, while Drop’s concealed terminal illness forces reckoning with mortality. A cherished photograph from Chibori "Tivoli" Urayasu, a distant classmate, becomes a tactile reminder of stifled yearning and missed connections.

Drop’s death plunges Roma into self-destructive spirals until a map to Iceland—a place entwined with Drop’s history—ignites purpose. Accompanied by Toto, he navigates volcanic landscapes to locate a memorial telephone booth, reconciling grief with newfound agency. This odyssey dismantles his resignation to rural stagnation, replacing it with embryonic curiosity about life beyond inherited borders.

His journey concludes not with grand revelations, but quiet acceptance of friendship’s impermanence and adolescence’s transience. The horizons once marking limitations now whisper of uncharted possibilities, reshaping a farmer’s son into someone tentatively willing to seek them.