Touching Darkness — Scott Westerfeld

Bixby, Oklahoma, is full of secrets.
some come out at midnight.
some should stay hidden.

As the Midnighters search for the truth about the secret hour, they uncover terrifying mysteries woven into the very fabric of Bixby's history, and a conspiracy that touches the world of daylight.

This time Jessica Day is not the only Midnighter in mortal danger, and if the group can't find a way to come together, they could lose one of their own . . . forever.