Three friends navigate mid-life crises: a blocked writer, a disillusioned doctor, and a charming man facing bankruptcy and divorce. As their struggles strain friendships, a younger man captures the attention of one friend's wife, complicating their lives further.
A drunken, self-destructive woman called Betty wanders into a Parisian bar where she meets middle-aged alcoholic Laure. Laure decides to take care of Betty. Recovering in a hotel room, Betty begins to recount to Laure the story of her bourgeois life and her unhappy and unfaithful marriage.
Doctor Valois has invented the "flashage", a cure for depressed people. After having tested it on monkeys, he tries with a first human patient, Alain Durieux. This is great success, everybody's happy except may be Alain's wife, Jeanne, who's worrying about the changes in Alain's personality. Other patients use the treatment with similar successes, and Valois's happy about it. But the monkeys are changing: non-cured ones are made mad by the over-stability and stereotyped behaviour of the cured ones. So are the humans. When Valois realises he can't stop the process, he decides to "flash" himself.
