From the Mixed-up Files of Mrs. Basil E. Frankweiler

From the Mixed-up Files of Mrs. Basil E. Frankweiler by E. L. Konigsburg

A suburban girl decides to run away from home to New York City. She enlists her younger brother to join her. She has found an unused train ticket they can take. Her brother has a good amount of money earned from playing war with other kids. They hide their stuff in their musical instrument cases and then go off towards school, only to hop the train to the city. There, they plan on staying in the Metropolitan Museum of Art. They hide out around closing time, then sneak to their area to sleep. They bathe in the fountain (which they also discovered to be a source of income.) They do voyage to other areas of the city.

They see a new statue at the museum that is rumoured to be from Michelangelo. It was purchased cheaply at an auction from a wealthy lady. They decide to find out more. They do library research and carefully look at it to identify a stamp that could identify it as original. They send a letter to the museum. (They type the letter on demo typewriter and open a PO box to receive responses.) Alas, the museum responds that they already knew about that and continue to investigate.

Finally, the kids decide to go visit the rich lady. There they agree to tell the lady the details of their experience in return for details on the statue. The lady has proof of the statue's provenance. However, she does not want to share it. She is willing to give it to the kids in her will after she passes away. She also agrees to return the kids to their home in her Rolls Royce. In the end, we learn that her lawyer is the kid's grandfather.

Through their journey in the city, the kids learn to get along better and build off each other's strengths. They also learn to get bold and solve problems. The book is told somewhat from the view of the rich lady, with many "clippings" included.