Mr. Magoo heads to a used car lot hoping to buy Waldo a new car for his birthday promising Waldo, "I'll be back with a little surprise for you". The crooked car salesman notices how myopic Magoo is and takes advantage of it by over-pricing the car Magoo chooses. Magoo accepts but the car salesman gets his just desserts when he unwittingly goes for a harrowing test drive with Magoo taking him to an amusement park where Magoo leads the car to the top of roller coasters and ferris wheels among other things with a police officer in hot pursuit.
