The story concerns the unsanctioned efforts of a covert unit to gather evidence about illegal arms shipments with the unwitting help of an embassy employee. When it appears that she is about to ruin everything by getting married on a weekend which is important to their operation, project director Le Squale (the Shark) (Jean Reno) directs that someone must seduce the woman's fiance so that she'll call off the weekend. Little does he know that the woman chosen is his own girlfriend -- the only one of his agents who is sufficiently thin to be alluring. One thing after another leads to the near failure of the operation -- including the efforts of the repentant fiance (Christian Clavier) to win his girlfriend back.