This article contains spoilers about the season 4 premiere of Sherlock . Read at your own risk.Take heart, Cumber-whatever-you-want-to-call-yourselves. Benedict Cumberbatch is back as Sherlock Holmes , and unlike last year's letdown of Christmas special, he's not wasted on some Victorian-era flashback that turned out to all just be a dream. Nope, tonight's season 4 premiere was firmly rooted in the present-day and was (sob) all too real.Mary Watson (Amanda Abbington) is dead. Not Sherlock Holmes dead or Irene Adler dead or even Moriarty dead (because at this point we're not sure what's going on with that guy). Like, actually dead. (This may be convenient for Abbington and co-star Martin "John Watson" Freeman given their just-announced breakup , but it's pretty upsetting for Holmes heads.)Watson's missus had quite an episode. The beginning of "The Six Thatchers" saw the former secret agent giving birth to the couple's daughter, Rosamund Mary (remember that name). Before long, however, she'd turned up as a person of interest in Sherlock's latest case, which ultimately led to her fatal shooting.Some backstory: Sherlock, conveniently exonerated for killing Charles Augustus Magnussen (Lars Mikkelsen) so he could pursue any and all leads pertaining to that bigger fish, Moriarty (Andrew Scott), spent the episode investigating the destruction of six busts depicting former British Prime Minister Margaret Thatcher. Sherlock correctly guessed that the culprit wasn't just someone railing against the Iron Lady's anti-union policies some three decades after the fact, but he got everything else wrong. The bust-breaking spree didn't link back to his arch-enemy Moriarty — they implicated his friend, Mary, the very person he'd vowed to protect.Back before she was pretending to be a nurse who would end up marrying Sherlock's BFF, Mary was part of a four-member team of secret agents (A.G.R.A.) charged with rescuing hostages the British embassy in Tbilisi, Georgia six years ago. The mission fell apart, people died, and her former assassin pal, Ajay, now wants Mary dead as revenge for her "betrayal." Ajay, incidentally, was the one smashing up the Thatcher busts, because he'd hidden an incriminating memory stick in one of them.