Simon Belin is an actor touring the provinces with his company. Although talented he has never been given the opportunity to shine on stage. It is always Bérimont, a matinée idol past his best, who gets the lead roles. One day however, Simon is witness to a murder. Subjected to the pressure of justice, of his agent and of his own wish for publicity, he identifies a suspect, Ferrari, without being certain he is the real culprit. Singled out by his action he becomes the toast of the town.Overnight he replaces Bérimont as the star of the play. But Ferrari, who had been sentenced to twenty years in prison, escapes and threatens him ; from now on he has ... three days to live.