"Where's the man with the megaphone?"
The fair boy shook his head.
"This is an island. At least I think it's an island. That's a reef out in the sea. Perhaps there aren't any grownups anywhere."
The fat boy looked startled.
"There was that pilot. But he wasn't in the passenger cabin, he was up in front."
...
"Aren't there any grownups at all?"
"I don't think so."
The fair boy said this solemnly; but then the delight of a realized ambition overcame him. In the middle of the scar he stood on his head and grinned at the reversed fat boy.
“No grownups!"
What statement best expresses the theme of this passage?