In the early 20th-century, Frenchman Claude meets Englishwoman Ann in Paris. Ann invites him to her family home, intending him for her sister Muriel. Claude falls for Muriel, but families demand year-long separation before approving marriage.

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.