The time is the turbulent late Meiji era, in the aftermath of the Russo-Japanese War. The setting is the vast, harsh northern frontier of Hokkaido, a land of dense forests, freezing winters, and lingering military tensions. The story shifts focus from the famous treasure hunt of Saichi Sugimoto and Asirpa to the dark past of one of the series' most complex antagonists: First Lieutenant Tsurumi Tokushiro of the 7th Division.

Before the events of the main Golden Kamuy narrative, Tsurumi is already a man driven by a mysterious and powerful aspiration. The novel explores his time during the Russo-Japanese War, a brutal conflict that shaped his psyche and forged his unyielding will. It delves into the shocking encounters and harrowing experiences that transformed him into the manipulative and charismatic leader willing to sacrifice anything for his goals. The narrative follows Tsurumi’s rise within the ranks of the notorious 7th Division, a unit known for its ferocity and loyalty to its commander, Lieutenant General Hanazawa. Through a series of missions on the battlefield and in the shadows of military intelligence, the novel reveals the origins of his fixation on the stolen Ainu gold and the tattooed convicts of Abashiri Prison. It portrays the early formation of his inner circle, including loyal soldiers like Second Lieutenant Koito Otonoshin and the unhinged Lieutenant Tsukishima Hajime, showing how he gathered these damaged men under his banner.

The novel’s narrative arcs trace Tsurumi’s psychological deterioration and strategic genius. One arc follows a covert operation behind enemy lines, where Tsurumi first employs the deceptive tactics and ruthless pragmatism that define him. Another arc focuses on his relationship with Wilk, the leader of the Ainu guerrilla fighters, and the tragic events that set Tsurumi on the path to obtain the gold by any means necessary. A final arc bridges the gap between the war and the beginning of the main series, showing Tsurumi establishing his base of operations and beginning his hunt for the tattooed prisoners, setting the stage for the bloody conflict to come. The novel is written by historical mystery author Amon Ibuki, with illustrations by series creator Satoru Noda, and provides a crucial deep dive into the motivations of one of manga's most memorable villains. A limited edition of the book also includes a Blu-ray with an original anime adaptation of the popular chapters The Lightning Thief and Viper Ogin.