The June sun shone lazily through the dusty windows of the Distillery High School in Old Chojny. A crowd of students pushed their way through the narrow corridors, chatting half-heartedly about the upcoming graduation, planned trips and recent school events. At the same moment, Magda, Michal and Dawid, three friends from class IVc, met under the notice board, on which hung a large poster announcing the "Last Bell Night". - What do you think, is there going to be something interesting this time? - Magda asked, fixing her thick, dark hair and casting a glance at the weary teachers passing by. Michal smiled from the corner of his mouth - Remember last year? Someone smuggled a Bluetooth speaker into the chemistry office and played the school anthem at full volume there. Everyone was running away from the principal. David, usually low-key, seemed particularly preoccupied this time. - I got a strange message on Messenger this morning. From an unknown sender. There was just one sentence: 'Come to the old gymnasium at midnight tonight. You will witness something you won't forget for the rest of your life." Silence fell. The sunny patches on the floor seemed to tremble nervously as if they too were listening for what was going to happen. Magda looked at David in disbelief. - And are you going to go there? - Maybe it's a joke - Michal added, but uncertainty could be heard in his voice. The old gymnasium, which had been closed for two years because the roof was being repaired, was a place where, according to the students, various unexplained things happened. Once school flags disappeared there, and another time someone found old, dust-covered textbooks thrown in the middle of the pitch that no one had ever seen before. The trio decided to meet up in the evening. After lessons, they each went home, but all the time the thought of the night's excursion was rattling around in their heads. The final bell was about to ring, and with it came the end not only of the school year, but also of an era in their lives. They knew that something like this was not to be missed. When midnight struck, complete darkness already reigned around the old hall, interrupted only by the bluish light from a forgotten street lamp. Quietly creeping through a side door, Magda, Michal and David stepped inside. The smell of dust and old wood enveloped them almost immediately. Waiting in the middle of the room was a figure wrapped in a wide black cloak. In one hand she held a translucent envelope and in the other hung a small silver key. She looked at them penetratingly and then lifted the envelope up. - 'Are you two ready? - She asked quietly. At that moment the door behind them slammed shut with a clatter, the lights dimmed and there was a silence in which the hearts of the three friends beat faster and faster....