The Aurora Circus came to town unannounced. Posters with colourful balloons and glittering characters appeared on advertising poles literally out of nowhere. Lena, a 13-year-old lover of magic and mystery books, felt she had to go there. That evening she dragged her 14-year-old brother, Adam, under the huge dome of the circus tent. Inside, the air smelled of candyfloss and caramel and the lights flashed with a riot of colours. There were acrobats suspended under the very roof, a clown with strangely sad eyes and an illusionist who cast a shadow bigger than himself. But what attracted their attention most was a girl in a silver mask who, instead of speaking, moved with the grace of a cat and handed out mysterious cards to the audience. Lena noticed that her card was blank. Adam, on the other hand, discovered the symbol of a broken key engraved on his. Soon the lights dimmed and an old wooden carriage pulled into the arena. The illusionist pulled a watch from his pocket and held it just above Lena's head. At the same moment, a barely audible whisper rang out around him: "Not everything you see is real..." People started whispering, someone behind them suddenly stood up and ran out of the tent. Lena and Adam looked at each other anxiously, clutching their cards in their hands. When the girl in the mask returned and stood in front of them, Lena felt a strange shiver down her spine. The girl whispered only: "Follow me if you want to know the truth." Lena looked at Adam. Everyone around them froze, and time seemed to stand still for a moment. Lena and Adam decided to get up from their seats and follow the mysterious figure into the depths of the circus, not knowing where it would lead them....