The old villa Pod Kasztanami had always seemed a bit strange to Jagoda, Bartek and Marcel. Now, during the longest holiday of their lives, they all lived there together - because the villa belonged to Jagoda's grandmother. It was full of dusty books, paintings with gold frames and a huge, creaking staircase that creaked under the slightest step. The first few days were spent searching for the secret passage and watching the bats that circled above the garden at night, but no one imagined that the real adventure was just beginning. One afternoon - when the sun was warming the roof tiles and the wind was rustling the leaves of an old chestnut tree - Berry found a very old leather notebook in the library. The cover was as red as a ruby and decorated with a silver flashing motif. - Look! - she called out to Bartek and Marcel. The friends immediately ran inside. As soon as Bartek touched the cover, a blue glow appeared around his fingers and the air felt like just before a storm. - Wow! - whispered Marcel. - What was that? Berry opened the notebook and saw that each page began to glow a different colour as their fingers touched the pages: blue, green, yellow. And then, right in front of them, on the wall of the room appeared a strange, luminous writing that neither of them could read. The letters swirled, merged together, splashed light across the room, and the notebook began to vibrate in Berry's hands. - 'Look, something's happening to your hand! - shouted Bartek suddenly. Marcel was under the impression that he could move things around the room without touching them - first he knocked over a book on the table, then he lifted an old pencil case. Before they had time to say anything, all the lights went out and the library door slammed with a bang. The hum of thousands of voices echoed around them, and strange shadows began to fall through the dusty windows....