On her eighteenth birthday, Cleo is given clues for a mysterious scavenger hunt that sends her around Columbus, Ohio, and through her past relationship with Declan, who drowned on a group rafting trip the previous year.

"Gabriella Mallory, AP student and perfect-daughter-in-training, stands barefoot on a public toilet for three hours while her school is on lockdown. Someone has planted a bomb and she is hiding. The bomb is defused but the would-be-bomber is still at large. And everyone at Central High School is a suspect. The school starts a top-secret crisis help line and Gabi is invited to join. When she does, she is drawn into a suspenseful game of cat and mouse...