Gaston Bernod is a Parisian bus driver. Honest, upright and hard-working, he is held in high esteem by his superiors. Gaston has always pampered "his" bus, going as far as to equip it with a fuel-saving device of his invention. Very close to his vehicle, he may have somewhat neglected his wife Paulette, who lets herself got round by the smooth words of Pierrot. The gigolo has indeed managed to persuade her to follow him to the Mont Saint-Michel, "a wonderful nest for their burgeoning love" as he says. The trouble is that Gaston, while driving his dear 84, catches sight of the car, and suddenly aware of his misfortune, sees red. He immediately sets off in pursuit of the culprits, involving his load of helpless passengers in the chase.
In his will, the late Jérôme Armandy has expressed the wish to have all the surviving members of his family summoned to the Château de l'Etang, in Provence. Firmin, Jérôme's servant, asks Claude, a Montmartre artist, to organize the reunion, to find the sum of 17 million francs which is hidden there (as a child he had been told by Armandy where the hiding place was) and to divide the amount between the different heirs. But a series of odd facts occur: Claude is knocked unconscious as he is busy opening the hiding place door; one of the heirs gets killed; and even more astounding, the dead man reappears and... asks his money back!
Beautiful and adored by the public, the great actress Florence once faulted with Remi, a disreputable individual. A little girl was born who lives in the countryside. Dorcier, the director, would like to marry Florence and wonders about her private life and her past existence. A jealous rival unleashes slander.
