In the wilderness of Hokkaido, the Japanese people Aina live in harmony with nature. Kotan Nakamura-Young Ain, who lives in the world, until he meets the tiger. This tiger, Dan, escaped from the train, who took him to the zoo. Together they detect mysterious ruins hidden underground. Inside the ruins of Kotan and Dan detect the old man by the name of UPPO, which lives there. He tells the boy and tiger about three keys to a fantastic treasure. It so happened that the evil secloud was also looking for a treasure and shoots in UPPO. Before death, UPPO gives one of the keys to the cat. Now Kotan and Dan are drawn into an ugly battle, when numerous villains pursue them to try to get all three keys to qualify for the treasure.