The 'Aurora' circus came to town suddenly and unannounced, setting up a huge colourful tent in the deserted square behind the school. Posters appeared on the poles one morning, as if they had sprung from the mist: "The world's most extraordinary show! Only three nights!". Lena and Bartek, the 13-year-olds next door, were as curious as ever. Even when others laughed that circuses were a relic, they couldn't help themselves. They sneaked through the side streets to get a close look at the vehicles and the bizarre cages that looked like they had come from a completely different world. On the day of the first performance, Lena felt uneasy. Something about the Aurora circus seemed different - the air smelled strange and the performers looked as if they had no shade. Even the clowns had their faces covered with masks, their eyes glowing with a pale blue light. Bartek joked that it was probably all just a special effect. Even so, Lena couldn't stop peering surreptitiously backstage, searching for answers to questions she didn't dare ask out loud. As the audience cheered during the fire juggler's performance, Lena noticed a small door under the arena, almost invisible just behind the curtain. It seemed to her that someone winked at her. When the show was over and the tent was almost deserted, Lena whispered in Bartek's ear that they should go check that door. They silently snuck through the still wafting smell of candyfloss and the swirling echo of the music until they stood in front of the secret entrance. A moment's hesitation - Bartek looked at Lena, Lena at Bartek. The door creaked open and swung open of its own accord. Behind the door there was a thick, milky mist. Somewhere in the distance, there was a strange rustling and laughter with a metallic sound. Lena held out her hand and took the first step. Bartek moved behind her, although his heart was pounding like a hammer. Just at that moment, a door slammed behind their backs and golden lights and unfamiliar, fragile silhouettes began to emerge from the depths of the mist. Lena and Bartek froze as the headlights flashed and...