From the Mixed-Up Files of Mrs. Basil E. Frankweiler takes the form of a letter from Mrs. Basil E. Frankweiler to her lawyer, Saxonberg. And what a letter it is.
Twelve-year-old
Claudia Kinkaid decides to run away from home with the help of her
little brother, Jamie (who is just nine years old). With Jamie's money
and Claudia's smarts, they bust out of that suburban joint and run to
somewhere that any kid would love. Disneyland? The rainforest? Sweden?
Nope—they end up at the Metropolitan Museum of Art. Less kid-friendly,
but more filled with pretty, elegant things.
See More Here:http://www.shmoop.com/from-the-mixed-up-files/summary.html
The setting will most likely affect the plot in the way that the power failure will hinder the movie and video games as the girl, her parents and guests are not done yet with the cake and food at the table and as read in the story, they would afterwards watch a new-release movie, and later they girls would play video games until time to go sleep, but now with the power cut they will not be able to do such things because there will not be power for the TV not for the console.
Emerson is making a claim that people often take natural phenomena such as stars for granted.
Hope this helps :)