On one stormy evening, two siblings, Kuba and Lena, were bushwhacking through the attic of their grandfather Antoni's old house. The place had always seemed full of secrets to them, but that day they discovered something truly extraordinary. In a dusty wooden box, between rusty coins and postcards from a hundred years ago, lay a strange pocket watch. It was silver, with an engraving of mysterious characters on the lid. Cuba, who had a special talent for tinkering, couldn't help himself and pressed a small button on the side of the watch. Suddenly, blue light flashed across the room and images began to swirl around them - the first knights, flowing ships, dinosaurs! Lena grabbed her brother's hand, her heart beating like crazy. After a while, everything went quiet. They opened their eyes and were surprised to see that they were in the middle of a cobbled square in an unknown city. Around them were people dressed in long, colourful tunics, and horse-drawn carts drove along the streets. Above them was a huge clock tower, whose hands moved in a completely strange way - sometimes even backwards! Cuba looked at his watch, which he held tightly in his hand, and saw that the hands on it were spinning faster and faster. Lena noticed that someone was watching them right next to them - an older man with glasses, holding a similar watch. Before they had time to react, the man smiled mysteriously and moved towards the narrow, dark alley. Could it be that he knows where they came from? Is the watch leading them to something important? The siblings hesitated only for a moment, then decided to follow the stranger, unaware that the greatest adventure of their lives was about to begin....