Has trouble traveled to Button or was it always there?

This book can be read as a stand alone, but it technically fits into the Whiskers and Words series between books 3 and 4. Enjoy! Traveling carnivals are known for their thrills and illusions. When one rolls into Button in early October, Louisa Henry can’t help but be suspicious. Rationally, Lou knows carnivals aren’t magical or menacing like they’re often portrayed in novels. Yet, right before her eyes, a woman walks into a mirror maze and doesn't come out. Just like that, she disappears without a trace. Lou knows something sinister is at play. The question is: are the villains part of the carnival or local? Will Lou find the murderer before the carnival disappears once more?