Rebecca Zamolo is on a mission to save her summer. Instead of going to camp like she’d planned, she’s been stuck in summer school. But today is the day! She’s going to present her final science assignment—using her Nana’s borrowed vintage zoetrope—and then she’ll be free to have fun. But as Becca and her classmates wait for her teacher to arrive, a menacing voice comes over the intercom claiming to be the Game Master! The kids quickly discover that the Game Master has locked the doors, scared off the teachers, and made it clear that if Becca and her friends don’t solve the clues that have been left behind, they’ll never get back Becca’s irreplaceable zoetrope, never finish summer school, and never get to enjoy what’s left of their summer vacations. Becca doesn’t know who is behind this, but she won’t let the Game Master win.