Two men sit in an isolated cabin exchanging stories about their past. Their past is our future, a post-Google Glass world where mobile technology is implanted directly into the optic nerve so, for example, it becomes possible to "block" other people, preventing communication in real life as well as online. Black Mirror is back for this one-off Christmas spec-fi drama. For the unitiated, Channel 4's Black Mirror is a series of speculative fiction TV dramas created by Charlie Brooker, a twenty-first century Twilight Zone with stand-alone dramas inspired by the rise of digital media tech. Brooker has always been the ultimate hatchet-wielding reviewer - for this episode, satirical targets include friend-blocking, online pick-up gurus, and personal assistants such as Siri or Cortana. As with previous mini-series, the acting in this episode is super: great performances particularly from a creepy Jon Hamm. The combination of the three subplots is OK but personally I think the id...