At the beginning of the 20th century, Claude Roc, a young middle-class Frenchman, befriends Ann, an Englishwoman. While spending time in England with Ann’s family, Claude falls in love with her sister Muriel, but both families lay down a year-long separation without contact before they may marry.

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.