Synopsis: Brave Dan

Living in harmony with nature, the Ainu people of Hokkaido, Japan, coexist peacefully with their surroundings. However, Kotan Nakamura's tranquil existence is disrupted when he encounters Dan, an escaped tiger from a train bound for the zoo. Together, they stumble upon a set of enigmatic ruins buried below the ground. There, they meet Upopo, an elderly inhabitant of the ruins, who enlightens the duo about the existence of three keys that unlock a treasure trove. Unfortunately, the notorious Sekkoku Kou is also coveting the prize and murders Upopo, leaving Kotan with one of the keys. Now, Kotan and Dan find themselves embroiled in a perilous struggle as several malefactors pursue them to obtain the keys and claim the treasure.