Rémi is a man trapped in a deteriorating marriage. When his wife is unexpectedly killed in a car accident, Rémi is left with his stepdaughter, Marion, who chooses to stay with him rather than live with her birth father. After the initial shock passes, Rémi is caught off-guard when Marion begins expressing her attraction to him. Initially repulsed, Marion's mature beauty wears him down as he finally caves to her seductions.

The third in a series of films featuring François Truffaut's alter-ego, Antoine Doinel, 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.

Parisian everyman Antoine Doinel has married his sweetheart Christine Darbon, and the newlyweds have set up a cozy domestic life of selling flowers and giving violin lessons while Antoine fitfully works on his long-gestating novel. As Christine becomes pregnant with the couple's first child, Antoine finds himself enraptured with a young Japanese beauty. The complications change the course of their relationship forever.

A young widow discovers that her late husband has left her 10 messages intended to help ease her pain and start a new life.