Kasari plot
In the Sitex factory, someone closed the safe door while the keys were inside. In addition to the keys, there are also important documents that have to be discussed at the ministry the next day. The management asks Lieutenant Rybák of the police for help and he knows only one way to open the safe: the ex-safe cracker Procházka. He has since changed his life and changed his name to Fiala. After much urging from Rybák, Fiala gives in and opens the safe. Two weeks later, however, the safe is broken open again and emptied. Fiala is of course the prime suspect, but Rybák believes in his innocence.