An intimate story of the enduring bond of friendship between two hard-living men, set against a sweeping backdrop: the American West, post-World War II, in its twilight. Pete and Big Boy are masters of the prairie, but ultimately face trickier terrain: the human heart.

When neighborhood kids begin vanishing, Jenny suspects her child psychologist husband, Carter, may be resuming the deranged experiments his father performed on Carter when he was young. Now, it falls to Jenny to unravel the mystery. And as more children disappear, she fears for her own child's safety.

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.