In Episode 8 of Golden Kamuy Season 4, the crew returns to Hokkaido and plans to find the gold themselves by creating a conflict between Hijikata and Tsurumi. Ainu leader Nispa proposes a solution to their financial problems by suggesting they help a local kotan fight a man-eating bear, a Wenkamuy, who is terrorizing gold miners near a river rich in gold and is a precious metal called "white" - actually platinum.
On their search for gold, Sugimoto and his team meet Heita, a gold miner who has made a surprising fortune by mining the river's platinum mixed with gold. In a surprising twist, Heita turns out to be a notorious criminal known as "Brown Bear Man" haunted by his traumatic past tied to the story of a Wenkamuy. Haunted by his dark past and guilt for tricking a Wenkamuy into killing his own family, Heita has escaped his tormented conscience by impersonating various people.
Sugimoto and his team try to help Heita face his inner demon. In doing so, they discover that Heita's inner Wenkamuy is a manifestation of his guilt and fears. His quest for gold led to the downfall of his family and his own transformation into a murderous "Wenkamuy". Heita believed that only by killing another human could he momentarily break free of the Wenkamuy's possession.
The episode ends with Sugimoto engaging in an intense battle against Heita's inner Wenkamuy, leading to a climactic revelation. Sugimoto's victory allows Heita to finally face his past and find peace, providing an important reminder of the importance of truth and the destructive power of greed.The complex narrative shows the psychological depth of the characters and their fight against inner demons and paints a grim picture of the consequences of greed and guilt.