Night always falls faster here than anywhere else. The Black Lake, hidden among the tangled branches of the Forest of the Moon, reflected the pale glow of the stars, giving the illusion that the sky was immersed in water. The flitting shadows, the crackle of a breaking branch, the distant hooting of an owl - all created an atmosphere that made the inhabitants of the nearby village avoid this place after dark. But that night, four teenagers - Lena, Igor, Sara and Wojtek - went there of their own free will. For them, the Black Lake was not only a place of stories whispered around campfires, but also a boundary between the known and the unknown. And it was this unknown that attracted them most. Lena was the initiator of the expedition - a tall girl with dark hair, in whom the shadow of a smile was perpetually visible. Igor, her cousin, wore a washed-out jacket and never parted with his camera, hoping to capture something amazing. Sara, who had read more about magic than she would like to admit, stayed close to Wojtek, the only one who knew this forest better than his own backyard. They stopped by the shore, where the thick mist seemed to pulsate to the rhythm of invisible waves. "Have you heard of the lake skylights?" - chuckled Sara, breaking the tense silence. Igor replied in a half-hearted voice: "Who hasn't heard? They say they only appear when someone throws a stone into the deepest place." Lena looked at them defiantly, then pulled a small, smooth pebble from her pocket. As Lena took a swing and threw the stone into the darkness, everyone held their breath. The wave spread out in a wide arc and light began to emerge from the depths of the lake. At first single dots, as if someone was scattering diamond dust on the water, then more and more, until the whole surface began to shine. Igor lifted the camera in a flash, Sara squeezed Wojtek's hand. Then the mist broke away from the surface and began to dance in the air, forming shapes resembling the silhouettes of figures. A draughty metallic sound came from the forest and a blast of cold pierced the air. Lena took a step back when suddenly the luminous figures turned their heads towards them. The shadow passing just behind them stopped and a golden fire flashed in its eyes. Igor pressed the shutter button, and for a moment it seemed as if time stood still. Wojtek asked in a whisper: "Do you guys see it too?". At the same moment, the lake seemed to swirl with light, and the water parted in the middle, revealing a narrow staircase leading deep into the darkness. A choice appeared before the friends that changed everything. Lena took the first step towards the stairs as another sound echoed through the trees....