Betty, a young alcoholic woman, is caught while cheating on her bourgeois husband. Wasting no time, he and his family arrange a quick divorce settlement, ousting her from home and keeping her away from the two children the couple have. One night she ends up in a restaurant called Le Trou (The Hole), where she meets Laure, an older woman, an alcoholic herself. Laure decides to take care of Betty after hearing the heart-breaking stories of her being a victim of her husband's rich and ruthless high society family. Betty receives care and friendship from Laure, who's in a relationship with Mario, the restaurant's owner. Betty's envy toward Laure, especially regarding her relationship with Mario, grows each day and eventually drives Betty to contrive the means to conquer her new friend's lover. Laure realizes she has made a mistake by trusting Betty, and things soon begin to fall apart between them. Betty's true colors are now visible and she sees her life at a point of no return, as she has selfishly stomped on the last chance she had of being a better person.
Lawrence O'Toole of Entertainment Weekly rated Betty a B+, praising Trintignant's "smashing performance" and calling the film "Disturbing, compelling, and very smart stuff."[3] In the Chicago Sun-Times, Roger Ebert noted that the film "creates an entirely different order of suspense from the ordinary 'suspense' film. Watching it, in the same week I saw two conventional Hollywood 'thrillers', was like being invited to participate with the depths of my mind instead of just the shallow surface."[4]John Simon of the National Review, in addition to praising the performances of Trintignant and Audran, described Betty as "one of the most well-behavedly bone-chilling horror stories of all time".[5]