Film narrative

For my film 'The Briefcase' i have been thinking about the narrative of the film, because it is only the opening to a film which will be the exposition, this is the opening premise and setting the scene, it will end with a small development part. The i will start the film will not inform the audience too much so they can guess what will happen so i will try to tell the story in a specific and unique way, as if i am going to make a full length film.