The Secret Hour

This is the first book in New York Times bestselling author Scott Westerfeld's Midnighters series.
A few nights after Jessica Day arrives in Bixby, Oklahoma, she wakes up at midnight to find the entire world frozen. For one secret hour each night, the town belongs to the dark creatures that haunt the shadows. And only a small group of people--Jessica included--is free to move about then. They are The Midnighters.
The Secret Hour is the first book in the Midnighters trilogy, from the acclaimed New York Times bestselling author of the Uglies series.