From The Mixed-Up Files of Mrs. Basil E. Frankweiler by e.l. koningsburg

 

 This book hooked me straight away.  But it wasn't until towards the end that I realized who the narrator was… probably missed some clues there.

 

So Claudia and her younger brother run away – but not out of town but to the Metropolitan Museum of Art in New York City.

 

Claudia and her fortunately tight fisted brother cope remarkably well.  They get interested in the provenance of a statue of an angel.

 

The story is told in a compelling way without talking down to the children's readers.  There is humour as well as acknowledgment of the worry their families are going through.

 

I can't tell you what happens because you'll want to read it yourself!