In 1930 in Paris, Dr Léon Galipeau examines 59-year-old Louis Martinet. Convinced that his patient has a maximum of two years to live, Galipeau convinces his brother Emile to use his 'viager' (life annuity) to buy Martinet's lovely country house in the fishing village of Saint-Tropez. (The 'viager' is a French system whereby someone with a lump sum buys a house from an old person, repaying them by instalments.)
Thinking Dr Galipeau is right, despite the fact that the doctor is always wrong whenever he says something (a running gag in the movie), Emile, under the advice of the notary dealing with the life annuity contract, accepts to index the 'viager' each year following the course of aluminium - a popular investment in the 1930s.
Despite Dr Galipeau's repeated claims Martinet isn't long for this life, as the years go by the elderly Martinet gets better and better, and the price of the 'viager' keeps getting higher. Finally, fed up with this sick man who won't die, the whole Galipeau family decide to try to get rid of Martinet. Their attempts become more and more desperate as time goes.
In 1940, an attempt to make Martinet pass for a German spy is foiled by bad timing, as it happens on the day of France's surrender. In 1943, they try to make Martinez pass for a Gaullist and a Résistant. Sadly, the letter is not delivered—until the Libération, upon which their letter allows Martinet to become a decorated hero. A few years later, during a visit of Martinet to Paris, the Galipeau attempt to make him have a heart attack, to no avail as the old man is perfectly healthy and quite happy to climb steps, smoke and drink… and so on.
- Michel Serrault : Louis Martinet
- Michel Galabru : doctor Léon Galipeau
- Claude Brasseur : Noël Galipeau
- Rosy Varte : Elvire Galipeau
- Odette Laure : Marguerite Galipeau
- Jean-Pierre Darras : Émile Galipeau
- Yves Robert : Capitaine Bucigny-Dumaine
- Jean Richard : Jo
- Madeleine Clervanne : Grandma Galipeau
- Noël Roquevert : Grandpa Galipeau
- Gérard Depardieu : Victor
- Bernard Lavalette : Mayor of Saint-Tropez
- Jean Carmet : Maître Vierzon
- Gabriel Jabbour : Monsieur Levasseur
- Paul Préboist : The cheese maker