Promise Me (Myron Bolitar #8) by Harlan Coben

The school year is almost over. In these last pressure cooker months of high school, some kids will make the all too common and all too dangerous mistake of drinking and driving. But Myron is determined to help keep his friends’ children safe, and so he makes two neighborhood girls promise him that if they are ever in a bind but are afraid to call their parents, they will call him.

Several nights later, the call comes at two a.m. The next day, a girl is missing, and Myron is the last person who saw her. Desperate to fulfill a well-intentioned promise turned horribly wrong, Myron races to find her before she’s gone forever.