Zlatko Kovač, a provincial professor, gets the job in the big city's school, only to find out that his red-employment is not random. Professor Toth, the man he replaced, has died under the strange circumstances. Kovac meets a variety of strange people in his school's collective, and it was not long before they came up with the new body. However, the police is unable to solve the case, but he takes the matter into his own hands and setting a trap for a murderer on a school manifestation.