Philip always thought that Primary School 9 was the most ordinary school in the world. Nevertheless, he liked it - especially for the recesses on the playground and the funny fooling around with Sonia and Michael. However, that morning, when he walked into Class 204 with his friends, he felt strange. On the blackboard someone had written in big letters: "Get ready for something unusual!". Sonia, inquisitive as usual, immediately asked the most important question: - Who wrote it? After all, it's not Ms Kasia's handwriting. Michael shrugged his shoulders: - Maybe someone from the eighth grade is making a joke. Or the caretaker? Philip walked closer to the blackboard. The letters looked as if they had been drawn with coloured chalk that glinted in the light. When he touched one of them, a quiet sound spread through the classroom, as if someone had moved a chair across the floor, even though no one else was in the room. Suddenly the books on the lady's desk began to move. One of them opened in the middle and a small blue piece of paper fell out from inside. Sonia ran over and picked it up. On the card was a drawing of a school clock, and underneath it was the inscription: "Time passes differently when you look carefully". Philip looked at the clock hanging above the door. The hands were moving faster than usual and stopped exactly at 10:10 - even though their lesson had just started. - 'Oi, that's not normal...' whispered Michael. At that moment, the classroom door closed on its own and the lights dimmed. The coloured chalkboard letters began to glow, forming new words: "Find the key before time runs out." Philip, Sonia and Michael looked after each other with wide-open eyes. As the lockers by the window rustled, they realised they were in for something none of them had ever experienced before at this school....