Under the streets of Warsaw, where the official plans of the city end and maps show only a dark spot, lay an abandoned metro station called 'Szczęśliwice'. No trains had been running there for decades, and few people knew of its existence. However, for Hania, Majek and Szymon, this very place was the beginning of the strangest adventure of their lives. That evening, they were going to see the graffiti that was legendary among high school students. With torches in their hands, they dashed through the dark corridors of the station. The echo of their feet echoed off the cold walls, and the air was strangely electric. - 'I have a feeling that someone has been here recently,' whispered Simon, pointing to fresh mud marks. - 'Maybe it's just rats,' laughed Hania, although she herself was also a little tense. Suddenly Majka stopped abruptly. - Look! - she said, pointing at something under the bench. There lay a silver, mysterious device resembling a compass, but with three needles and strange symbols on the dial. - What is that? - Simon asked, already reaching for the strange object. As soon as he touched the compass, the needles began to rotate frantically and a quiet, pulsating melody came from the device. Then the wall in front of them began to shimmer and a luminous portal appeared on it. - Look, it's... I think it's a portal! - exclaimed Hania. In the portal they could see a strange, futuristic city, floating above the ground. The three friends looked at each other with a mixture of fear and excitement. There was a mystery in the air and a feeling that if they crossed this threshold, they would never be the same again. Then someone's voice came to them from the portal: - If you are ready, come in. We are waiting for you...