Jagna has always felt best where the sun struggled to squeeze through the dense treetops and the air smelled of moss and damp earth. Together with her cousin Stas, she often escaped to the forest that stretched just outside their village. The Old Forest, the adults said, was full of ancient secrets and ancient legends. That morning, Jagna waited under the great oak tree, twirling in her hands the owl plume she had found moments before. Staś arrived, panting after a quick climb up the hill. - I brought the map! - he wheezed, showing a piece of yellowish paper with smudged lines. - Did you say it was drawn by your great-grandfather? - asked Jagna with a glint in her eye. - 'Yes! Look, it must be an old path,' he pointed to a strangely winding sign. Under the watchful gaze of the jays, they moved deeper into the forest, laughing and being careful not to get lost among the thicket. Soon they came to a place they had never seen before: among the ferns and mosses was a narrow crevice, partly covered by the roots of a large beech tree. A mysterious murmur came from inside, as if someone was whispering or singing softly. - Maybe it's the mermaids? - whispered Jagna, recalling her grandmother's stories about forest spirits. Staś squinted his eyes and reached his hand towards the entrance. Suddenly, the ground beneath their feet trembled and a warm, golden light began to emerge from the hole. The birds around went quiet as if on command. - Are we going in? - asked Staś in a half-hearted voice. Jagna looked into the darkness lit up by a flickering light. What will they find on the other side - a treasure hidden by ancient Slavs, a lost animal or perhaps something completely unexpected? The trees rustled, as if they wanted to tell them something....