Ever since her mom passed away, twelve-year-old Megumi "Meg" Mizuno has been spiraling. After too many low grades and cut classes, she's been expelled from school--apparently, everyone else has moved past her grief and expects the same from her. Her dad secures her a spot at the prestigious Leland Chase Academy, a boarding school in the middle-of-nowhere New York, called the Last Chance Academy by its student body. If Meg can't make it work there, she'll be forced to live with her horrible aunt.

At first, Leland Chase seems like an average, if very strict, boarding school, though Meg tentatively warms up to her roommate and some of their classmates. Then, one night, a mysterious envelope appears under her door, inviting Meg and her roommate to participate in a scavenger hunt. The only rules: don't get caught by faculty or staff and no cheating. The grand prize? A luxury stay at a fancy resort in California. And after learning her dad has plans to sell their family home--with all its memories of Mom--Meg knows she has to win the competition and use the trip to convince Dad to stay.

Thanks to her mom, who taught her how to solve ciphers, Meg has a knack for puzzles she uses to get ahead in the hunt. But she quickly learns that her classmates seem to have their own sets of skills keeping them in the competition. And as they get deeper in the game, Meg and her fellow competitors realize the anonymous creator has their own agenda...and LCA isn't quite what it seems.