Simon went to the countryside with his family every weekend. He liked these trips - the silence, the smells of the forest, and the river meandering just behind his great-grandfather's house. This summer, more than anything else, he was dreaming of an adventure of some kind. On a Sunday morning, armed with his camera and his new-found friend Lena, he set off on his bike along the riverbank. Lena was a born explorer - tall boots, a rucksack containing everything she could possibly need for an unusual adventure: from string to jam sandwiches. There was something electrifying about the air that day, and the sky took on a strangely purple hue. Simon couldn't help but glance up. At one point they stopped by an old bridge, which the adults said was about to collapse. After all, some people avoided this place; it was even said that at night you could hear the laughter of children from a hundred years ago. Lena walked closer, looking at the moss-covered bricks. Suddenly, right at the base of the pillar, her shoe caught on something hard. She bent down and swept her hand over the ground. - Come and see! - she called out to Simon. There was a strange metal door hidden under the ground. Completely incongruous with its surroundings, almost invisible if you didn't know where to look. They opened it with difficulty - a cool breeze blew from inside and a faint light came out. They hesitated at first, but Lena finally decided: - We are explorers after all, no? Let's take a look inside! Behind the door, a dark corridor waited, which spiraled downwards. The walls shimmered with strange symbols that neither of them had seen before. Simon pulled out his phone, trying to take a picture, but the screen glowed green and went out. It was impossible to call for help - they were on their own. They went below and the corridor suddenly opened into a small room. In the centre stood an old wooden frame, resembling a huge mirror. Instead of a reflection, a swirling image was visible: a misty forest, strange creatures, cities whose roofs glowed blue. Lena took a step forward; Simon stopped her by the shoulder. - Maybe we shouldn't... - he started, but Lena had already put a hand on his shoulder. The space trembled and the air around them began to swirl with violent force. Suddenly, the floor began to shake, and a quiet, metallic rustling sound came from behind the door to the corridor. A light flashed from the frame, which pierced the darkness and began to draw them inside. Simon and Lena looked at each other, feeling a mixture of excitement and anxiety. Before they could decide whether to enter or flee, the swirling landscape behind the frame unexpectedly changed, revealing a huge eye looking straight at them....