A murder has been committed in a block of flats in Pest. Almost all the dwellers of the building behave in a suspicious way at the beginning of the investigation, although it is their everyday lapses they try to hide. In spite of the janitor's unpleasant comments, light is gradually thrown upon the case.
A young woman on board of a bus notices that her watch has been stolen. The ticket collector keeps everybody on board, and upon the advice of a traffic police, they drive directly to the nearest police station.
