He portrays the fate of Rob Randalls, a boy living in a two-class society.
When Mike's mother finds Rob, she decides after initial hesitation to offer him to live with the family as an allegedly "nephew from Nepal".
The boy is fast to settle into the life of country aristocrats and attends school together with Mike starting in September.
This denial of reality and prejudices are creating a social order in which people are happy on their own, showing no interest in others.
The author wants to make the reader to question seemingly perfect conditions instead of accept them without a second thought.