Brain Camp (Paperback) by Susan Kim, Laurence Klavan

Neither artistic, dreamy Jenna nor surly, delinquent Lucas expected to find themselves at an invitation-only summer camp that turns problem children into prodigies. And yet, here they both are at Camp Fielding, settling in with all the other losers and misfits who've been shipped off by their parents in a last-ditch effort to produce a child worth bragging about.

But strange disappearances, spooky lights in the woods, and a chilling alteration that turns the dimmest, rowdiest campers into docile zombie Einsteins have Jenna and Lucas feeling more than a little suspicious . . . and a lot afraid.