6, life is carefully choreographed. School, study, and the occasional visit with his friend and classmate Safu. One fateful day, however, he takes a misstep, sheltering an injured boy his age from a typhoon. Known only as Rat, this boy is a VC – a fugitive living outside the computerized tapestry of city control – and helping him will throw Shion’s life into chaos and start him down a path to discovering the appalling secrets behind the superficial perfection of No. 6.