'Elementary' Season Finale Revelation: Who Is Moriarty?

"The Woman" - As Sherlock (Jonny Lee Miller) reels at the reappearance of his former lover, Irene Adler (Natalie Dormer), a series of flashbacks unravel the tumultuous events that led to his downfall into addiction , on the two hour season finale of "Elementary."

On last week's "Elementary," we finally saw Irene. We were nervous about how her presence would affect Watson and Holmes's dynamic; three is a crowd, always. Especially when the ex-lover is a beautiful kryptonite, played by Natalie Dormer. Ugh. She was so pretty, like her paintings, and when Holmes ran for her, Watson looked liked like Watts in "Some Kind of Wonderful" when Eric Stoltz bails on her.

But then, the finale changed everything.

What the what?! Irene is M. Irene is M. Irene is ... M!

We were prepared for Holmes to have a girlfriend who paints and sits around in flowery dresses with full makeup. Alas, no. Irene is a persona that M invented specifically to win over Holmes in England, because Irene is M, the sociopath mastermind behind countless murders. Back in the day, Holmes got in the way of her work. So she seduced him and then faked her death, figuring he'd be too messed up (score!) to get in the way of her Darth Vader-esque enterprises. Now, she's in America for business and calls his addiction proof that she's superior. Yes, ladies and gentlemen, M is that bad. And fans are reeling:

Irene/Moriarity explains herself:

Dormer, who plays Maergery Tyrell on "Game of Thrones," tells TV Guide, "You're very much aware that Irene Adler has to be the woman, the only woman who has ever gotten under the skin, or close to — to terrorize or to invigorate — Sherlock. She's intelligent, fiery, and Rob [Doherty, the show's executive producer] said she's got a bit of the devil in her. She's a nice yin to Sherlock's yang."

Indeed. Part one, "The Woman," transported us back in time to London, where we saw Holmes meet Irene. She can't even get through shaking his hand without gushing, "You're beautiful." She's a girl version of him talking turmeric and obscure historical facts. He figures out that she's a thief. She agrees to a date ... if the date is in the apartment. Meow.

Meanwhile, in present-day Manhattan, Holmes is in protective mode. Irene claims that a sicko named Stapleton kidnapped her and messed with her head by day and gave her white peonies by night. Holmes wants to protect her, so he moves her in and tells Watson to carry on investigating without him. In what plays like a droll "Three's Company," Watson gives Irene new clothes and Holmes puts the kettle on. It's so awkward that Watson offers to move out, but Holmes isn't totally whipped yet (thank God) and tells her, "This is your home." She's worried he's gonna fall off the wagon. He's worried she won't solve the case. Irene is in her room dancing to the oldies.

[Related: 'Elementary' Heads to London for Season 2 Premiere

The rest of the episode flies by as Watson, Gregson, and Marcus track down bad guys sans Holmes. It's weird but cute, because Watson channels Holmes when they find a jar of special paint at the Stapleton mansion. And yes, they do find the bad guys. We slip back to London to learn more about the dynamic between Holmes and Irene, which is kind of like Clarice Starling and Hannibal Lecter minus the cannibalism. She blows off Holmes. And Holmes is pissed; he wanted a second date. In perhaps the greatest justification of one-night stands of all time, Irene says she doesn't want another date because they must "preserve the integrity" of their "initial encounter." Ha! She should go move into the "Bad Girls Club" over on Oxygen. But yes, the smart, pretty people talk a lot and fall in love and have great chemistry in bed. Note: He thinks her moles look like a constellation.

Back in present-day America, Irene and Holmes freak out when they find a peony on her bed. Then we get more insight into Holmes through a flashback. In London, he went to visit Irene and found a note from M that she had been kidnapped. We're back in America, and it's easy to see why Holmes feels so compelled to protect his blond lover.

He brings her to his safe house (which is nicely decked out), but she wants him to run away with her. He goes to bid goodbye to Watson. But Watson smells a rat: Video proves that the peony deliverer really knew his way around the house. Watson thinks Irene is working for M. Hmmm. Meanwhile, the bad guys are doing stuff that moves the plot along. Irene is drying off after a shower when Holmes totally freaks out because her moles are gone. She says she never wants to see him again and she's outta there. Sad Holmes. She's gone. He's alone at home. And then he's not, because the a bad guy is shooting at him. The shooter refers to Moriarty as "she." And then the shooter gets shot. And then Irene walks in. Moriarty appears on the screen as Holmes gasps, "Moriarty."

Part 2 picks up where we left off, with Irene dishing on being a female psychopath — "as if men had a monopoly on murder" — and directly warning Holmes to back the F off: "You see puzzles. I see games. You are a game I'll win every time. I will hurt you worse than I did before. So please let me win."

Watson is obviously horrified by this development. She scrubs up to remove bullets from Holmes's back, which means that Holmes's shirt is off quite a bit. You gotta clean wounds on a regular basis, ya know. But it makes for nice bonding scenes.

M's bad-guy stuff in this episode is intense, involving Macedonian currency and reformed smugglers. Dominic Fumusa, Jackie's husband from "Nurse Jackie," is the worst kind of bad guy — one of M's henchmen, a security guard who lets the smuggler in to shoot the genuinely nice rich people he is hired to protect — and then lies about it. (Don't fret. Holmes totally figures out that he's a bad guy before it's too late.)

We get to have lunch at the Four Seasons (location clarified by @ElementaryStaff on Twitter). And it's a nice verbal catfight, with Irene/M calling Watson a "mascot." Well, Watson figures her out and tells Holmes to let her win, or at least think that she won. Holmes fakes an overdose and winds up in the hospital. Then, in a very satisfying "Murder, She Wrote"-style moment, Irene/M visits and talks about all kinds of illegal stuff. Holmes rips the oxygen tube out of his nose, and Watson and Co. come in and arrest her.

And then Watson and Holmes are home on the roof watching the beehives. Holmes names a bee after her. Not "a bee," mind you, a new species of bees. Such an underachiever, that Holmes, right?

There's no cliffhanger because we know who M is and where she is headed. Are you bummed that the book on M is closed, or are you excited for the next chapter? And are you happy that M is Irene, or do you wish they had held back on the big reveal until next season or, you know, never? Share your thoughts on the "Elementary" season finale in the comments.