"Repeatedly surprising and genuinely chilling." - E. Lockhart, bestselling author of We Were Liars and Genuine Fraud From the acclaimed author of The Leaving comes a new psychological thriller that challenges our trust in the electronic devices we keep close. Eden, Eli, Marwan, and Ilanka barely know each other beyond having a class or two together. But when they are all summoned via messaging app to an empty classroom after school, they find a small cube sitting on a desk. Its sides light up with rules for them: Do not tell anyone about the device. Never leave the device unattended. And then, Take me with you . . . or else. At first they think it's some kind of prank or a social experiment orchestrated by the school administration. Still, they follow its instructions until the newly-formed group starts to splinter. Nobody has time for these games—their lives are complicated enough. But the device seems increasingly invested in the private details of their lives. And disobeying its rules has scary—even life-threatening—consequences . . . This timely thriller probes our dependence on personal technology and challenges the notion that our devices are keeping us connected. The truth may very well be the opposite.