In the early twentieth century, Russo-Japanese War veteran Saichi Sugimoto searches the wilderness of Hokkaido for a hoard of hidden gold. With only a cryptic map and a native Ainu girl to help him, Saichi must also deal with every murderous cutthroat, bandit and rogue who knows about the treasure!

Sugimoto and Asirpa reach Lake Kussharo near Abashiri prison at last! The time has come to put all their plans to break into the prison and meet Noppera-bo into action. Their nemesis, Lieutenant Tsurumi, as always, is one step ahead and has his own agents inside Abashiri. Tsurumi himself is on the way, with a contingent of troops and a gunboat to back him up! But if anyone can survive being surrounded by enemies and still keep Asirpa safe in this deadly conflict it's Immortal Sugimoto!