Speed enters a no rules race and one of the contestants is a car that is over 200 yards long, the Mammoth Car.  Inspector Detector shows up to inspect the cars because he thinks that $200 million worth of gold is going to be smuggled out of the country.  During the race the driver of the Mammoth Car finds Speed a little suspicion and tries to kill him.  They wind up knocking him into a lake where he and Trixie sink to the bottom.