Zuza loved Tuesdays. It was when, after lessons, she could visit her grandmother, who lived right next to the forest, full of green secret corners. On that day, she ran through the school corridor as usual, holding her backpack in one hand and the leash of her beloved dog, Patch, in the other. Suddenly, by the lockers, she stopped because she heard quiet sobbing. It turned out that her friend Kuba had lost his new baseball cap. This was the third thing to disappear from the school this week! "That's impossible..." - whispered Kuba, looking around nervously. Zuza felt that something was wrong. She decided that she would try to solve this mystery. As soon as she stepped out in front of the building, Łatek started dragging her towards the old sports equipment locker. "Come on, I'll let you go soon!" - exclaimed Zuza, but suddenly something strange happened - as she stood in the shade of the old oak tree and squeezed the leash tighter, she felt a tingling in her fingers. She looked at her hands and... they had disappeared! Not believing her eyes, Zuza saw the grass through her and the leash with Patch seemed to levitate in the air. "Oh no, I think... have I disappeared?" Patch sensed something strange as he started barking louder and tugging on the leash. Zuza was scared and excited at the same time. What now? She shuffled between the bushes, trying to understand how she had caused this effect. Was it because she had received a strange amulet from her grandmother yesterday? Or was it something else? As she approached the door of the old storage room, she noticed that it was slightly ajar. Inside, someone was whispering. Zuza quietly looked inside, unsure if she was still invisible or if her hands were already visible. She could feel her heart beating hard. Suddenly, a figure in a sports sweatshirt emerged from around the corner, holding... the same Cuba cap! What would happen now? Will Zuza be spotted, will she manage to discover who is taking the students' things and why they are doing it? It will all depend on her courage and her newfound superpower...