Throughout the full run of the BBC’s “Sherlock,” it’s been clear Sherlock Holmes is not exactly one for social interaction, just as in any iteration of Sir Arthur Conan Doyle’s classic character. But with Benedict Cumberbatch’s performance as the brilliant detective, Stephen Moffat’s take on the character gives modern flair to this antisocial, drug addicted, brilliantly nuanced genius.

That lack of social skill, and inability to connect with others on an emotional level, has come to the fore in the opening moments of the Season 4 premiere, “The Six Thatchers” — which seems to be setting our hero on a path to self-destruction. Jim Moriarty (Andrew Scott) may be dead, but Sherlock’s obsession with the villain’s inevitable posthumous plan is putting clues everywhere he looks.

It’s normally Holmes’ wheelhouse — and what makes him brilliant at what he does — but that highly tuned attention to any Moriarty-adjacent detail has already dropped his guard to those that matter most in his life: John (Martin Freeman) and Mary Watson (Amanda Abbington).

sherlock season 4 john mary baby Isolating Sherlock: Moriartys final plan may already be in motion

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When Sherlock accepts the role of godfather to baby Rosamund without once looking up from his phone, we see just how far his obsession — with solving a case, with whatever chaos Moriarty still may have planned — might take him. Holmes’s addictive personality is out, in a new form — and full force.

Sherlock’s ego shines through most in these instances as the self-centered way he completely disregards the needs and feelings of John and Mary — but it’s also a key to our suspicion that Moriarty’s new game is already, as Sherlock would say it, “afoot.”

Without John Watson, Sherlock has no friends and no one to really connect with. Sure, there’s Mrs. Hudson (Una Stubbs), but her relationship with Holmes is mostly surface. Mycroft is around, but their relationship has always been a rocky one. And as we saw in Sunday’s Season 4 (Jan. 1) premiere, once Mary took that bullet, the dynamic between Sherlock and Watson changed — possibly forever.

In Mary’s posthumous plea to Sherlock, she asks him to save John. We’re not quite sure what that meant yet, but the “Miss Me” text on the envelope might be a subtle clue that things are not what they seem.

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While our hearts ache for John, and Sherlock for that matter, we can’t forget the signs in “The Six Thatchers” that Watson wasn’t the upstanding husband fans want him to be: That bit of infidelity is sure to come back and haunt him, and it’s possible this mysterious redheaded woman could have a bigger part to play in this whole thing moving forward.

The one thing that we know to be true is this: The impact of Mary’s death is sure to fracture the bond between Holmes and Watson. Grief is one thing, and Watson’s guilt over the infidelity we mentioned above is sure to boost his pain. And then, there’s the blame.

If Watson blames Holmes for Mary’s murder, and Moriarty is the genius in death as he was in life, then it’s not out of the question to assume Sherlock — through all his meticulous searching — failed to identify Moriarty’s plan already in action.

sherlock hero Isolating Sherlock: Moriartys final plan may already be in motion

And what would Sherlock Holmes be without the sound logic and assistance of Dr. Watson? In a vice-filled world of loneliness and resentment, like Dr. Gregory House (Hugh Laurie), his brother in literary inspiration — but much worse. Taking Mary out of the equation was just the start. Culverton Smith (Toby Jones) is the next step. And where it’s going after that, we shudder to think.

“Sherlock” airs Sundays at 9 p.m. ET/PT on PBS.

Posted by:Aaron Pruner

When he was a child, Aaron memorized the entire television lineup, just for fun. He once played Charlize Theron’s boyfriend in a Japanese car commercial. Aaron’s a lover of burritos and a hater of clowns. TV words to live by: "Strippers do nothing for me, but I will take a free breakfast buffet any time, any place."