Marcel, a simple-minded factory worker, is tricked into buying a high-priced American convertable car by a widow determined not to let it fall into the hands of her late husband's secretary/secret lover. Once in pocession of the car, Marcel only encounters one bad luck episode after another with the excessive gasoline consumtion, his wife trying to sell it to make ammends meet, getting into traffic jams, accidently riding into a car wash with the top down, and more.