Picking up when Season 2 left off, we have Sugimoto chasing after Kiroanke’s group, who are headed to Karafuto. As mentioned, after the Russo-Japanese War, southern Karafuto became Japanese territory. The series also mentions the 3 types of Ainu: Chishima, Hokkaido, & Karafuto Ainu. In which we end up meeting with a Karfuto Ainu named Enonoka. It seems she met Asirpa. No surprise after her father died and she thought Sugimoto died that she would be down in the dumps. Though there’s still the bit of her that gives Sugimoto the push forward.
As we get an update on both Tsurumi & Hijikata, Hijikata mentions how it is not really the gold that everyone is after. It is what lies beyond and basically what the gold can provide. In reality everyone has their own reasons they need the goal, and nothing is black or white. Of course it is not personal to those who die and fail to reach the gold. For Asirpa it would be for the Ainu, for Hijikata it is to bring back the Ezo Republic, and for Tsurumi it is the Japanese military.
Along with the recaps from the finale of S2, episode 1 here adapted chapters 140-142 as well as most of 143. It is clear the adaptation has a different endpoint goal, as the pacing is more concise than the first two seasons. The Tsurumi & Hijikata scenes aren’t really new but are dialogue that is used in different places.