The Valley of the Moist Ferns hid at the edge of an old forest, shrouded in the whispers of grandmothers and grandfathers. On this special night, when the moon was shining brighter than usual and the Kupala fires were already beginning to burn in the glades, Lena and David squeezed through a tangle of bushes and young trees. They wanted to find the fern flower - an ancient symbol of good luck, about which they had heard so many incredible stories. They had been friends since they were children, and it was their greatest joy to go trick-or-treating and exploring the area together. On this night, however, everything seemed different. The air was heavy with the smell of wet earth, and the indistinct silhouettes of the trees seemed to move to the rhythm of the leaping flames on the other side of the valley. The laughter and chants of people came from far away, but in the thicket it was just the two of them. "I don't think we've ever been here before," Lena said in a whisper, brushing the broad leaves away from her face. David nodded, looking around a little anxiously. "Do you think we'll really find a fern flower? Maybe we'll find something else?" - he asked, more in jest than with concern, though his voice was quieter than usual. Then a sound came to them from deep in the forest - a strange sound, like singing, but not human. It echoed among the trees. Lena squeezed the tiny torch she had taken out of her pocket tighter in her hand. "Did you hear it?" she asked, stopping. David inclined his head, trying to hear better. The sound repeated itself, closer this time - a melodious note, low and soft, as if the voice came from underground. Suddenly, right in front of them, among the ferns, a celadon light flashed. For a moment, Lena had the impression that she saw a small, pale figure, with long braided hair and eyes larger than a man's. Next to her, David opened his mouth wide in astonishment. Before they had time to take a step forward, the light flashed more strongly. At the same moment, a rustling sound came from a nearby bush, and a long, inhuman laugh pierced the air. Lena and David exchanged tense glances. A gust of wind suddenly began to swirl above their heads, and the forest shadows lengthened as if they had come to life. Could it be that they had come across a trail of creatures that, according to old legends, can only be found during the shortest night of the year? The boy wanted to say something, but the celadon figure nodded at them, then disappeared behind a curtain of ferns. Another chant rang out in the distance, this time clearer, as if calling out Lena and David, not knowing what was about to happen, moved slowly towards the light, which was still dancing somewhere in the thicket....