In the aftermath of the Russo-Japanese War in early 1900s Hokkaido, Saichi Sugimoto, known as 'Sugimoto the Immortal' for his bravery in battle, embarks on a quest for gold to honor a promise to his fallen comrade. Determined to support his friend's family, including a widow in need of eye treatment abroad, Sugimoto's journey takes an unexpected turn when he hears a drunken tale of a heinous crime and hidden treasure. Intrigued by the mystery, Sugimoto stumbles upon the dead man's coded tattoos revealing the gold's location. His life endangered by a bear, he is rescued by Asirpa, a young Ainu girl seeking justice for her people. Together, they form an unlikely alliance, combining Asirpa's hunting prowess with Sugimoto's resilience to pursue the elusive treasure—one driven by justice, the other by loyalty.