Here’s the background: This is the story of a wealthy family in Texas. One of the rich man’s sons has married an Hispanic woman and has a child with her. At that time, interracial marriages were very much disapproved of in Texas, and Hispanics were heavily discriminated against in much the same way that African Americans were. The rich man, played by Rock Hudson, is originally none too happy that his son has married a Hispanic woman, being full of the prejudices that were common at the time.
The grandfather (Rock Hudson), grandmother (Elizabeth Taylor), mother and baby have stopped in a diner to eat. Because they are with wealthy white people, the diner owner has grudgingly allowed the Hispanic woman and her child to be seated. But when a Hispanic family (who earlier had been depicted as having had a son die in World War II) comes in and tries to get served, the diner owner has had enough, and attempts to throw them out. Then watch what happens….