Eiga Doraemon Nobita no Nankyoku Kachikochi Dai Bôken

Unable to endure the midsummer heat, Doraemon transports Nobita and his friends to a huge iceberg floating in the South Pacific. While creating an amusement parks with the secret tool "Ice-working Iron" the group finds a mysterious golden ring in the ice. Upon closer examination, they determine that the ring was buried in Antarctica 100,000 years ago - before people could have lived there. Doraemon and friends head to Antarctica looking for the owner of the ring and come across the ruins of a huge city buried in the ice. Using Doraemon's Time Belt, the group travels back 100,000 years ago and meets the young girl Kara who is connected to the mysterious ring. But now the group must fight for survival as Doraemon faces the crisis of the entire Earth freezing.