I remember watching this movie with my father, and him being very excited. "It's High Noon. It's a classic," he explained as he sat down to watch. I sat with him, dubious, even for an eight-year-old.
I remember, too, waiting impatiently for the final showdown. It wasn't until later that I realized that wasn't the point of the movie.
Gary Cooper plays the marshall that ran the bad guys out of town some years ago. Now ready to retire to the shopkeeper's life with his new bride (Grace Kelly), his happy exit is marred by the news that the bad guys - now pardoned - are arriving on the noon train, and gunning for him.
His wife begs him to leave. His friends strongly suggest that he leave. The townspeople desert him to fend for himself. Nobody wants to get involved.
The social context is interesting. It's a pointed illustration of "fair-weather friends," and how people will hide behind any excuse -- family, politics, illness -- to get out of helping someone if it puts them on the line.