Simon and Lena were really looking forward to their summer holidays this year. For the first time, they were to spend the whole summer in their grandmother Bogumiła's old cottage, on the edge of an ancient forest, where the laughter of mermaids and the rustling of the wings of forest spirits were said to still be heard. In the evenings, the grandmother told them countless stories about the old Slavs, who were accompanied in everything by caring and playful deities. From early morning, the air smelled of conifers and damp earth, and the distant hooting of an owl sounded like an invitation. One day, just after breakfast, Lena urged her brother to take a trip into the heart of the forest. Grandma only blinked her eyes, handing them a bag of dried berries for the road. "Be careful, my dears. In the forest, not everything is as it seems," she said mysteriously. So off they went. The sun was playing among the treetops, the path was winding between the ferns and the birds were holding singing competitions. Suddenly Lena noticed something unusual - there was a symbol carved into the trunk of an old pine tree. It was a circle crossed by seven rays. The boy immediately remembered how his grandmother had called Swarog, the sun deity, and talked about his eye that guards the borders of the worlds. - See! I think that's the sign of Swarog that grandma talked about! - exclaimed Simon, touching the rough bark with his hand. At that moment, a giant crow flew down from the crown of the tree and sat right in front of them. Its coal-black eyes seemed to look straight into the souls of the children. Instead of flying away, the bird tilted its head and, with its beak, pointed out to them a path that had not been visible before - as if it had appeared suddenly, trampled in the tall grass. - Let's follow it! - whispered Lena, feeling a thrill of excitement. Simon nodded, and with a rustle of wings the crow moved ahead, glancing around every now and then, as if watching to make sure the siblings didn't get lost. The deeper they went, the more the forest seemed different. Colourful lights flitted from tree to tree and the wind carried strange, unfamiliar melodies. When they crossed a small stream, a clearing they had never seen before stretched out before them. A large, mossy egg-shaped boulder lay in the middle, and blue crickets and golden butterflies circled around it. A crow sat down on the stone, spread its wings and its shadow trembled, and suddenly a figure made of light and shadow appeared. - Who are you and why are you disturbing the peace of the old forest? - came a loud but warm voice, which could not be compared to anything the children had heard before. Simon and Lena looked at each other with concern, wondering whether they should answer or turn and run back. But the clearing seemed to have closed in and there was no longer any way back....