Leon and Zosia lived in a tenement in Sunken Clocks Street. This was no ordinary street, and their house also had something unusual - in the attic, among the cobwebs and forgotten trunks, stood the huge wooden clock of Alphonse's grandfather. Every evening, the hands of this clock would start to turn in the opposite direction, and a quiet ticking would come from inside, as if some creature lived inside. One cloudy afternoon, when her parents were busy cooking dinner, Leon suggested that Zosia go up to the attic together. Zosia loved secrets, and Leon was a master at discovering them. With a torch in one hand and a notebook in the other, they quietly climbed the creaking stairs. - Do you think he's really enchanted? - Zosia asked, looking at the clock. - You can hear it ticking when no one is winding it up! - whispered Leon. - Grandpa said that clocks can hide whole worlds. Zosia touched the clock face. The metal was cold and sort of trembled under her fingers. Suddenly, the hands began to move rapidly backwards, and a quiet click sounded from behind. A narrow slit slid between the digits. Without thinking for long, Leon slid his fingers into the slot and felt the mechanism move. The door of the clock opened wide with a creak. Behind them was not the usual mechanism, but a narrow, spiral corridor leading deep into the clock. The walls were covered with shiny gears and glowing cogs, and a mist that looked like the dust of time floated around. Zosia grabbed Leon's hand. - 'Shall we go in? - She whispered, looking concerned. Leon nodded his head. Together they crossed the threshold.... and suddenly they felt the floor disappear from under their feet! They fell deeper and deeper, and indistinct shadows of figures began to appear around them, clocks chiming and flying watch-birds hovering in the air. Finally they landed on a soft carpet of .... spinning hands. Suddenly a peculiar shadow appeared in the corridor. The strong smell of grease and dust hit their noses. In the semi-darkness, a quiet whisper could be heard: - Who dared to enter the Clock Labyrinth? Leon and Zosia looked at each other, and when they raised their heads, they saw in front of them....