Olek was always bored during visits to his grandfather Kazik's house. The old house at the end of the village was full of creaking floors and cobwebs, and the only curiosity was the big wooden clock standing in the living room. That summer, Olek was joined by his cousin Lena, who had an incredible imagination and was not afraid of any adventures. One afternoon, when the rain was drumming against the roof and there were no more new games to invent, Lena pressed her ear to the clock. - 'Something's humming up there,' she whispered. - Can you hear it? - Probably mice - muttered Olek, but Lena didn't give up. While Grandpa slept, the children began to examine the clock. Lena moved her hand over the engraved wood and suddenly... click! A panel slid away from one side, revealing a small door. Behind them there was darkness. Olek felt a thrill of excitement. - Are we going in? - Lena asked with a smile. Olek only nodded his head. They entered through a door, squeezing through a narrow tunnel. After a few steps, a chill and a strange, shining light surrounded them. The tunnel ended in a circular chamber, in the middle of which floated an old, golden hourglass. - This seems to... works? - Lena reached out to touch the hourglass. Before Olek had time to say anything, the sand in the hourglass began to spill faster and faster from one chamber to the next. The chamber lit up with a riot of colours, and the children felt as if the floor beneath them was caving in. Suddenly there was silence. Lena and Olek stood in the middle of a completely different place. There were strange buildings all around, people dressed in peculiar clothes, and the air smelled of fresh bread and smoke from bonfires. - Where... are we? - Olek looked at Lena with wide eyes. Then a loud voice rang out: - Hey, you there! Who are you? The children turned around slowly, looking straight into the eyes of a boy in a linen shirt with a wooden sword at his waist. Did Olek and Lena manage in this strange place? And how will they get home? They still have to wait for answers...