Saichi Sugimoto relentlessly pans for gold in early 1900s Hokkaido following the Russo-Japanese war. The ex-soldier, dubbed "Sugimoto the Immortal" for his death-defying actions in combat, pursues money in order to fulfill a promise made to his closest buddy before he was killed in action: to help his family, particularly his widow, who requires treatment for her worsening vision overseas. One day, an inebriated acquaintance tells Sugimoto about a guy who massacred a number of Ainu and took a wealth in gold. He concealed the gold someplace in Hokkaido before being apprehended by the authorities. The only hint to its whereabouts is the coded map he tattooed on the bodies of his cellmates in exchange for a part of the riches if they were to find it.