40-something Victor, humanities professor and amateur meteorologist, is a madcap, a friendly dabbler, who lives day by day, alongside is wife Anne.
JAM (Christian Clavier), a French "master of the universe" is on the brink of a major takeover when he starts suffering from anxiety attacks. His doctor (Lhermite) thinks it is to do with childhood experiences and suggests he searches back in his mind to something that could be the trigger and will prove to be the antidote.
The disappearance of a young woman puts two forensic police officers on the trail of a serial killer. Their fears are confirmed by the discovery of several corpses, what follows is a long hunt across Paris.
Samuel est psychanalyste. Toute la journée, il voit des patients exprimer des griefs, en particulier des adolescents rebelles qui méprisent leurs parents. Cette situation l'a conduit à voir d'un mauvais œil l'idée de sa paternité. C'est alors que sa compagne Mathilde lui annonce qu'elle est enceinte. Terrifié par l'idée, Samuel vit les neuf mois de grossesse de Mathilde plutôt comme un cauchemar, et les conseils de son ami Marc, homme à femmes mais célibataire endurci, n'arrangent rien à son angoisse. De leur côté, Georges et Dominique, la sœur de Marc, déjà parents de trois filles, affrontent sans inquiétude la quatrième grossesse de Dominique. L'expérience des uns va finalement avoir raison des appréhensions des autres, et entre les deux couples vont se tisser de solides nœuds d'amitié.
Julien, an honest policeman, is asked to infiltrate a terrorist organization. He soon meets the charming Brigitte. But soon, manipulated by his superior, Julien finds himself involved in a dangerous affair: a gigantic campaign of intoxication.
Martin Terrier wants to quit his job as a hired hitman, but his organized crime employers are unwilling to see him turned out to pasture, Terrier knows too much, and he is still useful to the organization. He escapes to the countryside where he meets Claire, and the two soon fall in love. Back in Paris to confront his employers, Terrier learns that they've stolen all his money from the bank. They give him an ultimatum—do one last job for them and he gets his money and his freedom...