The little dog Lotte gets a new baby sister: Roosi. Together they go on an adventure. Karl the raccoon and Viktor the fish are two scientists visiting their hometown of Gadgetville. There is an important contest this year. Whomever gets to make the mythical fire-breathing dragon, the oldest animal race in the world, sing the national anthem, will win. But they are not easy to find. Lotte and Roosi decide to help the scientists find these forgotten dragons to win the contest.