The old library building on the edge of town always seemed to Ania, Jakub and Lidka like a place from another era. In the evenings, it looked like it had been taken out of a Gothic novel, hiding endless labyrinths of bookcases and dark corners that even the librarian, Mrs Nykiel, didn’t want to talk about. One rainy afternoon, when the town seemed extinct amidst the thunder, the friends decided to stay in the library after closing time to find the lost Traveller’s Diary, about which legends circulated among the readers. The dim light and silence heightened the impression that secrets lurked here. As they searched the dusty shelves in the oldest part of the building, Lidka came across a heavy metal door, partly covered by a pile of old atlases. The door gave way under pressure, and the friends descended a narrow staircase into a small underground room. In the corner stood a monumental, intricately decorated clock with a strange symbol on the dial. Jakub carefully turned the hands of the clock as light flashed outside. Suddenly, the air swirled, the bookshelves began to blur, and the sounds of a completely different world were all around them. They found themselves in a completely unfamiliar, bustling place, and on the wall hung a poster with the date: 3 May 1939. They wanted to go back, but the entrance to the underground had disappeared, and somewhere in the crowd, someone shouted their names, as if they had been waiting for them for years…