Hello folks! I was wondering if any of you know what the title of this book is. I read this when I was young and I cannot remember the title anymore. It's about a mother and her son who got left behind in a mall and was accidentally locked in. Then they discover that there's a secret community inside the mall of people who were locked in and chose to live there, coming out only after the mall is already closed. Their community seemed happy and peaceful, until you tried to get out and go home. Does that ring a bell? I've been racking my brain for years but I really can't remember the title of that book.

This sounds like it might be Secrets of the Shopping Mall by Richard Peck, only the protags aren't a mother and son--they're an older girl who's running away and a younger boy she rescued from a pack of bullies, who decides to go with her. Sound familiar?