What if a close friend knew the ending to your novel 40 pages into it? What if that person were certain that it’s a work of art anyway—one that should not be changed under any circumstances, she says—but by the mysteries of circumstance or fate or coincidence, she happened to figure the whole thing out right away?

What if you still had time to change it? Would you?

And what if it’s not happening with a novel? What if it’s happening with one of the greatest TV shows of all time, right now?

What if it’s happening with Mad Men? Because it may be.

Two years ago, Lindsey Green wrote a theory about the end of Mad Men on Medium that, at the time, was greeted as beautiful, if far-fetched, fan fiction.

But season after season, episode after episode, the theory never really fell apart. Nothing was imminent, but nothing ruled out anything in her post.

Then this week’s episode aired and something became very clear.

“It started to look like either this is the ending of this show or this is getting really personal with [Mad Men creator] Matt Weiner,” Green tells The Daily Beast. “Hi, Matt!”

Here’s the theory: In Green’s post, “Where Don Draper Ends, D.B. Cooper Begins,” she supposes that Don Draper is about to pull his most daring identity theft yet—he's going to turn into a real, historical figure.

“D.B. Cooper” is the pseudonym of a man who permanently skipped town in November 1971 by skyjacking a Boeing 727 in the most Don Draperian way a man could skyjack an airplane. Clad in a suit and tie, Cooper handed a note to a flight attendant. She presumed it was his phone number until he whispered to her, “Miss, you’d better look at that note. I have a bomb.”

He then demanded four parachutes and $200,000, and, because it was 1971, he got just that. After a handoff in Seattle, he proceeded to tell the pilots to fly to Mexico. The pilots wound up flying to Reno under the guise of a refuel, but it didn’t matter. Cooper opened up the stair door at some point before the landing and disappeared into the wilderness with a suitcase full of money.

No one knows what happened to D.B. Cooper, just as nobody ever knew or cared what happened to Dick Whitman, the identity Don Draper abandoned in the Korean War for a fresh start. Of course, the difference is, Don Draper is a fake person with a fake name. D.B. Cooper is a real person with a fake name.

As Green’s theory outlines, similarities and clues are everywhere. Don’s former boss on the show is named Bert Cooper, and he was one of the only characters to know that Don is working under someone else’s identity. Bert Cooper famously didn’t care upon finding out about the identity shift—dispelling Don’s greatest fear—and shooed Don out of his office.

So that’s two-thirds of the assumed name in one character, but that’s not enough, right? After all, Bert Cooper died last season.

But guess who showed up as a ghostly visage in this week’s episode?

“People were sending me texts when Cooper showed up,” says Green.

Yep, Cooper’s character showed up in Don Draper’s Cadillac to dispense advice from heaven. And where was Don Draper driving? Just west, to nowhere in particular. After he uses somebody else’s identity to try to find a lost fling in the Midwest, the episode ends with him heading even farther west.

Maybe he’s going to Oregon?

“Earlier in the season, when it turned out that [SCDP] were never going to open the West Coast office, I got a little nervous. But I kept saying, ‘They’ve only got to get him out West once in the next few episodes,’” says Green. “So the second he got in the car, I knew.”

And what was the last thing Don Draper saw before leaving a stodgy ad meeting to take off on his road trip? A plane, two streaks behind it, flying over the New York City skyline.

“He’s started already using a different name. At this point, one way or another, I think Don Draper will no longer exist. How that forms and how it takes shape we’ll see over the next two episodes,” says Green. “I think Don Draper is over. Ever since Anna Draper died, he’s very clearly been seeking out a new identity.”

It’s all too perfect, and there’s more out there that confirms it. But here’s the craziest part: Green knew this was an option in Season 2. That season aired eight years ago.

She remembers the exact moment when it clicked. Green had been having some conversations a few weeks before with some friends about famous cold cases. She’s an unsolved mystery junkie, she says, so “D.B. Cooper” was a name known but not explored. She went and did some standard Wikipedia-ing a few days before watching Mad Men.

And then there was that moment in Season 2, Episode 11: The camera pans to Don Draper getting out of his car in Los Angeles for the first time, and Green saw it. Those sunglasses. He looks just like the police sketch of D.B. Cooper in those sunglasses. (That episode is called “The Jet Set,” by the way.)

“I was just like, ‘Wouldn’t it be cool if this is who he was?’” she says.

But she never thought anything of it. She assumed everyone in the world knew: Don Draper is D.B. Cooper. Duh. Esoteric period piece is about esoteric news event. Of course.

Except, well, nobody had thought of this. No one. Nobody had written it down on the Internet, at least. Then an intentionally cryptic, foreboding piece of Season 6 promotional art came out—it features Don Draper walking away from a departing plane—and Green felt compelled to tell the world, even if she was convinced she was not alone.

“I was absolutely sure it was one of those things where you think you have invented something very important or discovered a song, and then you go and tell someone else, and clearly you have not,” she says. “I wrote it in about 20 minutes. I had no expectations for it. I had no idea people were gonna care. I just wanted to have it in writing. I was convinced it was so obvious.”

Then she started to understand that if she didn’t invent this theory, she’s the only one who had the guts to go public with it. And since then, it’s never really gone away. It’s become a formative part of her identity. She doubled down last year when Bert Cooper died on the show—“That was the moment I really started to believe,” she says—and so did everybody else.

She’s been glued to Twitter during these last few episodes. People are finding her theory. People are looking her up to tell her she’s right.

TV conspiracy theories are not Green’s day job—she’s the head of communications at Bustle—but, emotionally, it’s starting to feel like one. In fact, she’s starting to wonder if she’s becoming a part-time pain in Matt Weiner’s ass.

“People who are recapping are taking it into account now and taking it seriously. I love TV. I love writing, so this is sort of a dream that it’s happening,” she says.

A reporter even asked Weiner about the theory directly back in January at the Television Critics Association press tour. Let’s say he didn’t deny it.

So this gets to the heart of it: If Weiner learned that he got found out—that his legendary ending was spoiled by a particularly clever PR person in New York City—would he ever think of changing the ending? Would keeping it diminish the art? Would changing it? Could Green have had an effect on the end of the show?

“I’ve asked myself that. I’m like, ‘Did I ruin it for myself? Did I ruin it for everybody?’ I get nervous about it. I think Matt is such a smart writer,” Green says. “It could go in so many ways.”

With two episodes to go, cards down, does Green really think this going to happen?

“I think deep down, it’s probably not going to happen. At the last moment, I think he’s gonna take a turn. I mean, basically, the show is about a study of behaviors—about what makes somebody behave the way they do. It’s a people zoo—the study of these people,” she says.

For now, Green is just basking in the glow of it. No matter what happens in the next two weeks, it was a hell of a run. No conspiracy theory has ever gotten the Cinderella run of credibility this one got—more and more arresting and believable until the last second. Even if this thing blows up and loses in the Conspiracy Theory Super Bowl in a couple of weeks, she’s just happy it got this far.

Maybe she’ll get a TV writing job out of it, she thinks. She should. Definitely more secure than falling out of an airplane with a pile of cash, anyway.

“I feel like I started a thing that feels really significant. It’s really cool. I had no idea it was going to catch on, so I’m still astounded by how close it might be,” says Green. “Either way, I’m going to watch the finale alone in a dark room and cry if I’m right or cry if I’m wrong.”

Oh, by the way, with two episodes left in Mad Men, the show looks like it’ll wrap up in 1971. In November 1971, D.B. Cooper fell out of a plane bound for Reno.