Arnold's poor dental checkup and a visit by Drummond's health-conscious sister, Sophia, launches Drummond on a campaign to have ""junk"" food machines banned from Arnold's school, even though Arnold's drive for his class' presidency may depend on keeping the machines in place.

Does Drummond have a third son, there's a young man at the door who claims he does and that he is.

When his girl friend plans on taking a drive with someone else, a careless Willis -- refusing to be outdone -- gets an idea for a real joy ride neither of them will forget.

An adamant Drummond ignores sister Sophia's pleas to get involved in a group effort to combat air pollution, until Kimberly becomes victimized by the unnatural phenomenon.

Aunt Sophia's matchmaking unites an unsuspecting Drummond with her ""working-class"" hairdresser, but a slip of Arnold's tongue ignites charges that Drummond is a snob, turning a ""budding romance"" into a roaring feud.