When Noemi first heard about the Oak Forest, she didn't believe in any old legends. After all, we live in the 21st century, she thought, and ancient Slavic spirits, russets and werewolves are just children's tales. But this summer, something had changed. In front of Noemi's class, her grandmother started telling incredible stories. She said that once upon a time, when the moon was full, you could meet a meridian in the Oak Forest or hear the whisper of a moksha, that there were things hidden under the great lonely oak tree that people had forgotten. Noemi, Bartek and Lena - a pack from primary school - decided to investigate on their own. One Saturday evening, when the rest of the village was huddling around the bonfires during Kupala Night, they took torches and old maps and set off to find evidence. The deeper they went into the forest, the quieter it became around them. The branches of the trees hummed as if they were whispering secrets to each other. Bartek joked that a housefly was about to jump out from behind a bush, but Lena had already stopped laughing when a strange greenish glow fell on the path. Ahead of them among the ferns appeared a root elm that looked like a gate, with the shadow of a figure barely visible inside. Was it just a play of light, or was someone... something... watching them? Suddenly, muffled laughter could be heard from deep within the forest, and a pair of luminous, dancing orbs rose above the trees. Noemi felt a shudder - she remembered her grandmother's words: "never go behind the light if you don't want to know the truth about your fate". The friends looked at each other, trying to decide whether to go on or run away. Then the shadow under the old gate moved more clearly, and all the torches went out at once....