Mr Carburettor is going to ban Flash from Silver hatch unless he learns how to do something useful. Can Flash learn how to be a good marshal in time? Hellie wants to be able to race like the cars. When he does join in he is accused of cheating. Hellie is upset and the cars annoyed… will they be able to make up before something disastrous happens? Marsha decides to be a mechanic but wears Big Chris out with her endless questions. Disaster strikes when Chris dozes off and doesn't listen to her properly…