Sherlock: The Six Thatchers

The detective returns to investigate the apparent return from the dead of his old enemy Moriarty, but another strange case is soon demanding his attention. Scotland Yard is baffled by a mysterious criminal who is defacing images of Margaret Thatcher, and Sherlock is convinced there is a more sinister purpose at work behind these acts of vandalism - but his investigation digs up Mary Watson's dark past as an assassin. Benedict Cumberbatch, Martin Freeman and Amanda Abbington return for a fourth series of the detective drama