“American Horror Story: Hotel” just dropped one helluva bombshell.

You know that 10 Commandments killer case John Lowe (Wes Bentley)’s been so obsessed with all season? Well, there’s a reason this thing’s been so personal for him all this time. Turns out, his little sleepwalking sessions were rather eventful indeed.

The Secret Trophy Room

We first back up to last week and the moment Wren got hit by a car. John Lowe goes after her and almost becomes road kill himself, but he’s too late. She’s dead. He recognizes the sight of her stillness as something he’d seen in the hotel pool (the same one he’s been repeatedly convinced wasn’t real).

So, he heads back there in search of some answers. Liz Taylor (Denis O’Hare) is first on the receiving end of John’s inquirous rage, but part of her job description is that she doesn’t scare very easily. “I swear to God, asshole. You touch me one more time, I will cut your throat while you sleep,” she warns after being grabbed by the former detective.

That’s when Hypodermic Sally (Sarah Paulson) chimes in just in time to diffuse the tension in the lobby and says she’s got some answers to offer up herself. She doesn’t promise the Ten Commandments Killer is in the room she takes him too -- it’s actually the place where James March died -- but she thinks it’ll help him solve the case.

She takes him to a secret storage room with a stash of body parts that have been there since “the beginning” (in 1926).

See, March had done an initial run of Ten Commandments-style killings himself, so whoever’s doing the bloody bidding nowadays is merely finishing his work. But who? Who indeed.

“Nobody let him in. He had a key,” Sally tells him. “Take my hand. It’s OK baby. It’s all OK baby … We’re almost there. There’s just a little more work to do.”

That’s when all the memories of him hammering nails in tongues and Wren helping him escape that church where the televangelist lost his spleen come back to him. After all, he’s the one who logged all the evidence, so he had easy access to take his, um, souvenirs for March’s closet of pain. So, yes, John Lowe is the Ten Commandments Killer he’s been looking for all along. BOOM.

“It’s you, John. It’s always been you,” Sally says. WHAT.

Confessions

Meanwhile, John Lowe’s only remaining friend in the department studies Wren’s corpse and tells his subordinate he wants to make sure John’s family’s OK. Good guy, that one? And John is grateful for that courtesy as he surprise-approaches him to offer up his confession -- not just for helping Wren escape the looney bin and assaulting a guard. For murder. The 10 Commandments murders, in fact.

“I remember where it all began now. It all started those first few days and nights at the Hotel Cortez,” he recounts. That’s when the detective notes that he’s only been living there for three weeks, while these killings have been going on for years.

Oh, but there’s an answer for that detail too. Turns out, John’s been palling it up with James March (Evan Peters) for years.

“The first time I walked into the Hotel Cortez was five years ago. I know that now,” he remembers. He’d just finished with that sad accidental asphyxiation case and wanted to fall off the wagon for the night “to forget.” That’s when he found himself at the bar of Liz Taylor at the Hotel Cortez and, eventually, at the table of James March -- thanks to a little coaxing by Donovan (Matt Bomer), who sees an opportunity to occupy his Countess’ former husband and relieve her of her dinnerly duties to him.

“The moment you walked into my suite, I was struck by the intensity of your aura,” March says, complimenting his blackened aura which he says either serves as a protective cloak to allow him to “focus on any task at hand” or means that he’s dominant -- “a man who is willing to do bad to do good.”

March ends up charming Lowe into a two-day-long chat about God’s law, man’s law, life and death. “I don’t need a judge to tell if someone’s guilty or not. I know. If they took the leash off, crime would drop in this city,” John fiercely says.

That’s when March pegs him as “the one” to finish his death-dealing design, but the Countess (Lady Gaga) sees a snag in his plan. “He won’t let go, he still has hope.” As in, a family who loves him. Ah, so that’s why she decided to steal his child from the beach carnival that day. Angryface.

His first kill was of a pedophile who'd brought a 10-year-old to the hotel to do ... something ... and since that's around the same age as Holden, this takes him right over the edge. He feels guilty right away -- but mostly because he liked doing the deed so very much. March asks him to finish his work and make himself lead detective.

Five years later, and it’s all finally coming back to him (The reason he couldn't remember before? “The Cortez is a selfish mistress, John … She’ll never let you take anything with you," according to Sally, who he's apparently been making whoop with this whole time). There may be “no such thing as justice anymore,” but John’s got his eyes open now.

An Unlikely Victim

Now that he's fully aware of what he's done/doing/will do, it's 100% him when he decides to carry out his original plan to take out his pal at the station. Well, he originally wanted to off his wife Alex (Chloe Sevigny), too, because he suspected their little coffee meeting was more than just a chat, but Sally talked him out of it because the murder was too close to home. But now, all bets are off. He doesn't have anything left to live for -- except Scarlett, but she doesn't want anything to do with him anymore after that in-house shooting incident.

So, bye-bye old friend. And another Commandment killing has been done.

But this time when he walks into the Hotel Cortez, he knows exactly who he is and what he's done, much to the delight of Iris (Kathy Bates), who's plum exhausted trying to play the "which John is which" game.

And March, of course, is happy as pie that he's finally got a full-on ally in his mania. "You can finally appreciate the beauty of your work. Death is your art. I stand in awe of your talent. But what will you do with it, now that you understand?" March asks.

"Two more," says John. But who? Dun dun dunnnnnnnn.