Spoiler alert! We're discussing important plot points and the ending of "Argylle" (in theaters now), so beware if you haven't seen it yet.

Who is the real Agent Argylle? It’s a mystery that gets revealed halfway through the spy comedy “Argylle.” More importantly, the movie's finale doles out clues to where the franchise goes next and which other film series it’s eyeing for a crossover.

In director Matthew Vaughn’s action-packed outing, reclusive spy novelist Elly Conway (Bryce Dallas Howard) discovers her plots are veering uncannily close to espionage situations in the real world. Shaggy spy Aidan (Sam Rockwell) helps keep Elly and her pet cat Alfie safe when the bad guys from the villainous Division come after them as they search for a master file revealing rogue agents. Elly also has reality-bending visions of her flattop-rocking fictional Agent Argylle (Henry Cavill), and along the way, Aidan and Elly search for the real Argylle … who just happens to be Elly herself.

What?! Add in the fact that in our real real world, there is an “Argylle” book written by someone named Elly Conway, and there’s a whole lot to unpack, especially with different ways for the franchise to go. “There is so much potential with this to move in multiple directions, and most of them unexpected, when it comes to the continuation of this universe,” Cavill says.

Let’s dig into the movie’s biggest reveals:

What is ‘Argylle’ about?

So much! The biggest deal is Elly’s revealed to be a CIA operative named Rachel Kyle (“R. Kyle,” get it?). She got amnesia after a fall into the Thames while on assignment and had a whole fictional backstory brainwashed into her by evil Division head honcho Ritter (Bryan Cranston) and henchwoman Ruth (Catherine O’Hara), who masquerade as Elly’s mom and dad.

But here’s another twist: Elly/Rachel, whose bestselling books were actually memories of her old adventures, turns out to be (gasp!) a Division double agent, and she’s mind-controlled back to being a baddie. Love ultimately conquers all, though, and she and Aidan defeat the Division – with help from spy pal Keira (Ariana DeBose) – and upload the master file to ex-CIA deputy director Alfred Solomon (Samuel L. Jackson).

'Argylle' review:A great spy comedy premise is buried by secret-agent chaos

What happens at the ending of 'Argylle'?

After saving the day, Howard’s character goes back to being novelist Elly and she’s at a book reading when, during a Q&A session, a square-jawed individual who’s the spitting image of the fictional Argylle stands up – though Cavill has a mullet and a Southern drawl instead of the flattop and British accent as this mystery guy. Elly looks surprised when he says to her, “I don’t have a question. But you probably have one or two for me.”

Vaughn is “obsessed” with mullets, he says. “I thought a flattop in the beginning and a mullet at the end sort of hopefully makes you lean in and think, what the hell is that all about?” But that tease to a potential sequel is “just to say we have a very fun storyline of Mullet Man, as we're calling him.”

Is there an ‘Argylle’ post-credit scene?

Affirmative! The scene starts 20 years earlier, at an English pub in the country called The King’s Man. A young man (Louis Partridge) walks in, introduces himself as Aubrey Argylle and says he's been sent there. A bartender bends down to pull out a wooden box that has a gun in it. “Now that’s a twist,” Argylle says as it cuts to black.

Vaughn explains that the movie plot revolves around “Argylle” books four and five, but this scene is actually from the first “Argylle” book, a real-deal spy novel that’s been released in stores and written by an “Elly Conway.” So this is a sneak peek at what a prequel could look like. That pub name also seems to be a gigantic tell that “Argylle” takes place in the same universe as Vaughn’s other spy franchise, “Kingsman,” with Taron Egerton and Colin Firth.

“All I'll say as a clue is not many people can make the beautiful Nehru collared suits that Argylle wears with pride,” Vaughn says, nodding to the Kingsman organization’s use of a London tailor shop as a front for its espionage escapades.

So who wrote ‘Argylle’? Is it Taylor Swift?

For a while during the run-up to the movie release, nobody really knew the identity of the Elly Conway behind the “Argylle” book, and it became a strangely viral mystery. An online conspiracy theory even popped up that Taylor Swift is Elly Conway because the movie character has the same kind of cat, a Scottish Fold, as the pop superstar. Vaughn even smacked down those rumors.

On Friday, the Telegraph in England finally dropped the news that Elly Conway is actually two writers: Australian author Terry Hayes ("I Am Pilgrim") and British thriller novelist Tammy Cohen. "It has been one of the most magnificently surreal experiences of my life and I've enjoyed (almost) every minute," Cohen wrote on X.

At least that's one less secret for Vaughn to keep. "The only thing anybody asks me bloody questions about is Elly Conway," he said before the reveal.

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