Moscow, 1902. The famous director Konstantin Stanislavsky, in search of inspiration for staging a new play, decides to get acquainted with the life of the city "bottom". He turns to Vladimir Gilyarovsky, a recognized expert on the Moscow slums, for help.
The hero of the film, the investigator of the UK, appears to the viewer as a cynical, calm person, ready to do anything to achieve his goals. But a series of events forces him to take a fresh look at himself. The hero is faced with a difficult choice, where on the one hand – a career and prosperity, and on the other – an act by which he can lose everything, even his life.… And here comes that very day - One real day that gives the hero the opportunity for moral rebirth and spiritual takeoff!