Nobody at the Władysław Jagiełło secondary school expects the school celebration to end in scandal and… death. Justyna Wysocka, the librarian, is put in charge of organising the celebrations for the school's fortieth anniversary. One of the main attractions is to be a presentation of keepsakes from a time capsule that has been found. When a photograph of a naked woman appears on the screen, the festive atmosphere evaporates. Justyna suspects that the pupils of class IIIc are responsible. But this is only the beginning. That very evening a fire breaks out at the school. A teacher about whom disturbing rumours had been circulating is killed. At the same time, a female pupil disappears, and a classmate discovers that she gave his address as the place she was supposedly going to – though she never arrived. The deeper the characters delve into the past, the darker the secrets that come to light. Who was the woman in the photograph? Why was it taken in a pupil's garden? And what is the meaning of the wooden cross that someone has put up years later in the same spot? At the school everyone has something to hide, and the story from years ago is not over yet...