Living in the post-zombie apocalypse has become routine for the lucky Metros who live in walled cities with sharpshooters. For those who live in the suburbs, however, life ain't so grand. Take a simple thing like a government-mandated education. Burbies like Savvy and his friends must take a two-hour bus ride into the nearest city every day just so they can go to high school. This would be the bus ride from hell, but for the enigmatic Haley, who was once a Metro but has since relocated to the suburbs. While Savvy tries to untangle her secret, he receives mysterious texts from I5HMA3L that warn of a locked door leading to the school basement, missing Burbies, and a threat that could destroy the entire school.