Pierre is married to Florence. Everything is fine in their relationship and at work. Manager of his father-in-law's factory, Pierre spends his days signing checks and his evenings watching TV. The years pass, monotonously, until a young new secretary arrives and Pierre starts to fantasize about a different love life.

Le Grand Amour is followed by Happy Anniversary (Heureux Anniversaire), a film about a woman holding dinner for her husband on their anniversary.