Gabriella Mallory was trapped in the girls' bathroom the day a bomb threat put the school on lockdown. It seemed like everything she'd been working for--AP classes, college applications--was about to be taken away. The police found the bomb in time, but not the bomber. He or she could be anyone--one of Gabi's friends, the guy she rejected, or the person leaving ominous notes all over school. It could even be one of the anonymous callers on the helpline where Gabi volunteers. When Gabi starts receiving messages from the bomber, she seems to be part of a twisted plan. Can Gabi find a way to stop another attack? Or will she become the first victim?