The school in Spruce had a reputation for being the dullest in the whole district - at least until one June afternoon. Lena, Marcel and Iga, a pack since forever, were just leaving class, sheltering from the rain under the entrance canopy. They were waiting for the bus, exchanging sarcastic remarks about their forthcoming baccalaureate and holiday plans, when Iga suddenly fell silent, staring at the overgrown hill behind the football field. - 'Did you see that? - She pointed to something in the distance. Behind the trees, at the top of the hill, was the sluggish silhouette of an old radio tower. It had stood abandoned for decades. At this hour, the fog was so thick that the structure looked almost unreal. At the same moment, Marcel took a walkie-talkie out of his backpack. An old piece of equipment he used to play with after school, because his father was a radio amateur. - Come on, do you want to eavesdrop on the conversations of truck drivers again? - Lena rolled her eyes. - 'No, listen... Marcel turned the knob, trying to catch anything but the crackling. Suddenly something strange sounded: a steady, low-pitched tone, then a crackle - and a female voice, almost in a whisper, pronouncing a string of numbers: "257... 014... Where are you...?". Everyone looked at each other. The signal went silent. Lena, whose shivers ran down her spine, lowered her gaze to the walkie-talkie. - Who could it be? - Maybe the number to the radio station? - Iga tried to sound rational, but tension echoed in her voice. - 'Or someone calling for help,' Marcel added, looking towards the tower. - There is a transmitter there. Maybe the signal is coming from there. We need to check it out. - Have you gone mad? It's almost dark. But no one could ignore the curiosity. Lena looked at the boys. There was an overgrown, forgotten path through the woods leading up to the tower. Although it was wet and slippery everywhere, they set off uphill, guided by the silvery light of the torch from their phone. The closer they got to the tower, the more clearly they felt uneasy, as if something was watching them from behind a tangle of branches. They stopped at a fence net, already rusted and damaged. Marcel put the walkie-talkie to his lips. - Hello, can anyone hear us? No answer. There was a grim, metallic sound in the distance, as if something had fallen to the floor inside the tower. - Did you hear that? Through a crack in the wall, Lena spotted a flicker of light inside the building, although there should have been only darkness. Pushing through the weeds, the three teenagers reached the door, which swung open under a gentle push. Inside, amidst the rubble and rust, stood.... At the same moment, the voice on the walkie-talkie spoke again, this time more clearly and pleadingly: "Be careful... Not everything is what it seems...". Silence fell. Lena, Marcel and Iga looked at each other, trying to decide whether to go in further, knowing that they were about to learn the secret of the abandoned tower - if they were ready for what awaited them there.