In a green glade, right next to an old oak tree, lived a little turtle called Theodore. Every day he basked in the sun and played among the leaves together with his friends: the cheerful mouse Mela and the curious sparrow Philip. One morning, Theodor noticed something shiny in the grass. He walked closer and discovered a tiny golden key. He was enchanted - he had never seen such a treasure before! - What is this key? - asked Mela, jumping up and down with curiosity. - Maybe it opens a secret door? - added Philip, flapping his wings. All three looked at each other with wide-open eyes. Are there really secrets to be discovered in the forest? Full of excitement, they set off towards the densest corner of the forest, where they had never been before. There, among the old leaves and tangled roots, they suddenly heard a quiet, strange sound.... What was that? And what does Theodore's mysterious turtle key really belong to?