The happening

It was just an average day at school, except it wasn't. When Grace's school has a blackout, so does the entire city. The only difference after the lights come back about an hour later is that the only people in the city left are the people inside the school, everyone else is gone. The only exception is the unknown voice that fills the speakers in the school instructing and informing everyone about the current social experiment that they are all currently in. Grace, Alex, Maria, and Jason are grouped together and find themselves in not only a social experiment, but also a killing spree, and they're the prey.