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.
A crotchety old coot wants his son and daughter-in-law to have kids so he can have grandchildren, but so far they haven't done so. In a somewhat ham-handed attempt to bring them closer together so they'll be in the mood to give them the grandchildren he wants, he winds up bringing them to the point where they're considering divorcing. He decides to change his tactics in order to achieve his goal.
Apparently a normal couple, Karen and Max are in fact agents for opposite sides of the "cold" war who have been assigned to marry each other and feed/steal intelligence. When they are both ordered to execute the other they realize that they have fallen in love.
It tells the love story of Lu Jin Nian and Qiao An Hao spanning 13 years. They first got to know each other in school, but later parted ways again due to some misunderstandings. Now, Jin Nian is the unapproachable king of the entertainment business while An Hao is a rookie in the same business. Fate lets Jin Nian and An Hao meet again and An Hao ends up becoming his fake wife.