Sofia lives in an orphanage, she is already thirteen years old, and she has lost hope of finding a family. But one day a man named Schlafen, a professor of anthropology, came to them. He stated that he wanted to adopt the girl and take her to his house on the lake. The professor told Sophia that she belongs to the clan of Thuban - this dragon defeated and imprisoned the cruel Pidhogr, a winged wyvern, in the bowels of the earth. Three thousand years later, Nidaogre makes itself known again. And now the dragon girl is called upon to fulfill her mission - to protect the world from endless evil.