When homeless 19-year-old Mel steps into the Greenvale Shopping Centre she’s only looking for a warm place to spend a cold London December. But behind its glittering displays the Greenvale hides dark corridors and each person who crosses Mel’s path is about to be drawn in. Mel’s arrival sets in motion an unstoppable chain of events that will have a life-changing effect on anyone who gets close to her. There's no privacy in the Greenvale, where technology reveals everything except for the identity of who is watching who.