Louis Stainval, a humble car washer at Mr. and Mrs. Grillot's garage, hits the lottery jackpot. It is the end of hardboiled egg time for him. One day, he helps a stranger who has just tried to kill himself for the umpteenth time. This man, Grandvivier, is a mediocre painter whose work is depressingly worthless. But the artist has produced a unique masterpiece, at least in Louis'eyes, his daughter Lucie. Falling in love with her at first sight, Louis soon decides to please his future father-in-law and works out a scheme. He invents the character of Van Patten, a rich buyer who has developed a burning passion for Grandvivier's art and poses as a go-between between the two men. Visit after visit, Louis buys a picture in Van Patten's name, which he immediately throws into the river...