In the ruins of civilization, a young girl's kindness and capacity for love will either save humanity — or wipe it out in this USA Today bestselling thriller Joss Whedon calls "heartfelt, remorseless, and painfully human." Melanie is a very special girl. Dr Caldwell calls her "our little genius." Every morning, Melanie waits in her cell to be collected for class. When they come for her, Sergeant keeps his gun pointed at her while two of his people strap her into the wheelchair. She thinks they don't like her. She jokes that she won't bite, but they don't laugh.