The article is devoted to the dramatic analysis of such a landmark film as “Casablanca” by M. Curtiz. The author looks into the picture from the standpoint of a heroic legend, the structure of which was revealed by J. Campbell in his book “The Hero with a Thousand Faces”. However, the analysis is carried out not only based on the “monomyth”, the author turns to such a type of film composition as the plot composition, which involves dividing the film according to the following parts of the plot: exposition, plot, development, climax, denouement, finale, their location relative to each other and their connection.This synthetic approach which takes into account not only the American method of plot construction but also theoretical developments of domestic film dramaturgy permits to recreate a holistic image of the film and to go into details about its scenario structure.The study is quite relevant, as students-playwrights and actively practicing screenwriters often face the problem of plot construction. The author hypothesizes that there are some universal scenario laws permitting to keep the viewer interested throughout the whole picture, from its first frame to the last one, and tries to prove it by parsing the plot-forming scenes of the film "Casablanca", defining the genre of the film as a whole, revealing its central thematic contradiction or theme and presenting the idea of the film with a fresh perspective.The scientific novelty of the study lies in the fact that the laws of the plot construction, being universal, are considered as a fairly stable system of the film’s semantic coordinates, in the least affected by specific taste preferences which are closely associated with art as such. And, since the theory of screenwriting is closely related to its practice, we may appeal to these laws and argue that their knowledge is not only a significant help when working on a film script, but also the most important condition for its creation.