An allegory about humankind progresses from a savage state to a civilized form, that is only a cover for its innate barbarism.

A tribe of primitive "mudpeople" encounter a croquet ball, rolling through their forest. Following it, they find themselves on a vast, deserted Long Island estate. Entering, they begin to become civilized and assume the stereotypical roles and dress of people at a weekend party. There follows an allegory of upper-class behavior. At last, they begin to devolve toward their original status, and after a battle at croquet, they disappear into the woods.—Frank Eggleston

The Mud People are one of a group of primitive and barbaric nomadic tribes that wander the forests. After following an errant croquet ball (which they don't know what it is), they stumble across a mansion that is empty of people but that still has all the lavish material possessions of its inhabitants. Slowly, the Mud People are transformed by their environment into sophisticates. Although they end up having elaborate dinner parties, playing croquet, talking about world events and arts and culture, it can be argued that they are more savage now than they were before the transformation.—Huggo