The third in a series of films (following The 400 Blows and the short Antoine and Collette) featuring writer-directed François Truffaut's alter-ego, Antoine Doinel (Leaud), the story resumes with Antoine being discharged from military service. His sweetheart Christine's father lands Antoine a job as a security guard, which he promptly loses. Stumbling into a position assisting a private detective, Antoine falls for his employers' seductive wife, Fabienne, and finds that he must choose between the older woman and Christine.
After being discharged from the army, Antoine Doinel centers a screwball comedy where he applies for different jobs and tries to make sense of his relationships with women.