SPOILER ALERT: This story contains spoilers for “Charlotte,” the fourth episode of “National Treasure: Edge of History,” now streaming on Disney+.

Rest assured, “National Treasure” fans: Justin Bartha knows some of you were hesitant to embrace Disney+’s new spin-off series “Edge of History.” He was too.

After all, it’s been 15 years since its sequel, “National Treasure: Books of Secrets,” hit theaters in 2007, marking the last time audiences spent time with Bartha’s Riley Poole.

The tech-savvy, sarcastic right hand of Nicolas Cage’s treasure-hunting historian Ben Gates remains one of the defining roles of Bartha’s career, alongside “The Hangover.” It’s also the only one he can watch with his daughters, so fans have them to thank for chipping away at his initial skepticism to guest star in the series’ fourth episode.

“To be honest, I didn’t jump aboard right away,” Bartha tells Variety. “But after talking with [the producers] and looking at my daughters, it was tough to turn my back.”

Over the last decade, making a third movie that would pay off the cliffhanger from the second movie — what “life-altering” American secret is on page 47!?! — has proven harder than stealing the Declaration of Independence.

Writer Chris Bremner was the latest to take a swing at a script in 2020. But since then, momentum shifted to “Edge of History,” the Disney+ episodic offshoot that follows Jess (Lisette Olivera), a DACA recipient living in Baton Rouge who finds herself in a race against an antiquities dealer (Catherine Zeta-Jones) for a Meso-American treasure tied to her lineage.

Justin Bartha and Lisette Olivera. Courtesy of Disney+

Despite existing in the same world as Ben and Riley, Cage is not slated to appear in the series, even though it shares crucial DNA with the original. It hails from Cormac and Marianne Wibberley, the writers of the films, and counts original director Jon Turtletaub and executive producer Jerry Bruckheimer among its producers.

This week, it also has Bartha, whose presence immediately gives fans hope the movies aren’t dead — and he didn’t come alone. In the series’ premiere episode, Jess’ journey began after a chance encounter with an ailing Peter Sandusky (Harvey Keitel), the FBI agent who hunted Ben and Riley in the films. Fellow FBI Agent Hendricks (Armando Riesco) also recurs.

In the episode, Riley arrives in Baton Rouge to attend Sandusky’s funeral — just in time to help Jess and company decipher a clue from Elvis himself they stole from Graceland.

Thanks to some helpful exposition, audiences learn Riley translated his “Templar Treasure” book into a hit podcast that’s being adapted into a streaming series. He’s also 15 years into a new treasure hunt with Ben, one Riley not-so-subtly confirms is tied to Page 47.

As for Ben, Riley reveals he’s still with Abigail (Diane Kruger), with whom he shares a dog named Charlotte (a nod to the sunken ship that opened the first film).

But where Riley goes, misadventure follows. At the wake, he and Jess get trapped in Sandusky’s secret clue room, which is programmed to suffocate intruders unless they decipher his password. With only his wits and Jess’ puzzle-solving prowess, the pair embark on an old-fashioned “National Treasure” clue-finding mission down to their last breaths.

Bartha spoke to Variety about reuniting with Riley for the ticking-clock episode, the franchise’s generational fandom, the latest on that third movie — and whether he knows what’s on Page 47.

Before the series offered you the chance to reprise this role, had you ever considered where Riley Poole might be now 15 years after the last movie?

Not really! But in a storytelling sense, we have been trying to get the third movie off the ground for quite awhile. Jon Turtletaub, the director of those movies, and I would, back in the day, write some stuff together and tinker around with what a third in the series would look like. So there were times where we asked what exactly is going on in the world, and what that meant for the treasure they would be hunting. But we never got as far as answering questions, like, is he married or those kinds of things.

Did you buy into the new series’ reveal that Riley is the host of a successful podcast that is being adapted into a streaming series?

I think it definitely makes sense that he’s trying to glean as much as he possibly can from this very important experience in his life in finding these treasures. He is kind of defined by it. Podcasting seems like the natural evolution from writing books about his experience and just trying to keep the spirit and the adventure alive. I’m not sure if there are many other outlets where you could do that these days, so it kind of seems like a perfect extension of him. I’m sure some will groan, “Of course, he’s a podcaster.” But everyone is a podcaster these days!

National Treasure: Book of Secrets (2007) Left to right: Diane Kruger, Justin Bartha, Nicolas Cage Courtesy of Disney

The audience sadly doesn’t get to hear Riley’s podcast in the show, but one has to imagine it is incredibly dense and scatter-brained, just like he is.

“Dense and scatter-brained” is the perfect description for Riley Poole, and is maybe even the title of his eventual autobiography.

You are clearly still passionate about a third “National Treasure” movie. So what were your initial thoughts when you heard Disney was focusing on this new spinoff series instead?

I was skeptical at first, if I’m going to be honest. But when I looked past my initial skepticism, I was excited to see what it was going to be. I have kids now, and I’m really desperate for something to watch with them. We made the original “National Treasure” almost 20 years ago, and those two movies are basically the only two movies I’ve ever made that my kids can watch. Being able to do something that my daughters can watch was what got me past the skepticism. And I’ve known the Wibberleys for a long time, and Jon and Jerry were involved. I knew the heart was in the right place, and they would respect the spirit of the franchise. To be honest, I didn’t jump aboard right away. But after talking with them and looking at my daughters, it was tough to turn my back.

Considering it has been almost 20 years since the original movie, what has this franchise meant to you? You seem very protective of it.

I love this character — he means a lot to me. He really does. There hasn’t been a week in the last 20 years that’s gone by without someone stopping me and talking about “National Treasure.” And the response has evolved over time. It really is a special thing and I think any type of extension that touches it, no matter what it is, is great.

How has the response evolved?

It’s wild. I made those movies when I was a kid in my early 20s. At first, it was such a huge opportunity as an actor and it afforded me a launching pad to my career. But as I got older, you realize the fans of the film are getting older too and having children, and it becomes this generational fandom. I’ve had the most profound experiences with these fans. Them telling me they watched it in the hospital with their mother who was dying, and it’s their favorite film. I swear I had dinner with someone whose son got into antiquities because they were obsessed with the movies as a kid. People have named their kids after Riley, and have tattoos of him.

Now, as a parent, you see the value in a really specific type of family entertainment that can provide this communal experience that feels really rare now. Like nothing else I’ve done, not even “The Hangover,” connects in such a real way and it’s been a gift for me and continues to be. Which is why I had to be involved in some type of way with the show.

Once you did sign on to guest star in “Edge of History,” what was your reaction to reading the script and realizing they planned to nearly suffocate Riley in an escape room nightmare scenario? They didn’t make your return easy for you.

Listen, I threw myself into it just like Riley does. It was such a fun episode, and I thought it was clever to mirror an escape room, which wasn’t a thing when we made the movies. Now that I’m thinking back on it, I almost passed out a couple of times during filming trying to look like I was running out of air. It was just a great way to dip in and out for Riley in the series.

What was it like having Lisette Olivera as a scene partner having worked so closely with Nicolas Cage in the movies?

She’s wonderful. She’s a super talented actress, and game for whatever. Working with her really brought me back, because on the movies, we spent so much time breaking down the script and making sure these seemingly ridiculous situations made sense and were entertaining and compelling. With the Wibberleys, we really locked back into our old ways of trying to get it exactly right, and Lisette seems like a great leader for this new group of young actors. It’s odd to say that I was the oldest actor on set that day — because I was the youngest actor on set for the movies.

For fans of the movies watching this episode, their ears are going to perk up because you nod to Page 47, the mysterious cliffhanger from the second movie’s Book of Secrets. In the wake scene for Harvey Keitel’s character, you specifically say you’ve got 47 reasons to keep quiet about your and Ben’s current project. Was this a tease to what could potentially be the subject of a third movie?

The Page 47 reference was something that I threw in there when we were filming. I just had to. But listen, there is still hope for another movie. Nic is obviously doing great, one of the greatest ever. Jerry just had a big hit with “Top Gun: Maverick,” and he is doing great. And the constant drum beat from the fans for a third movie just makes it a no-brainer for me.

Did the Wibberleys ever tell you what was on Page 47?

Oh, I know it all but I can’t tell you. You will have to write your local Disney representative and get the movie made to find out.

In the past year, Jerry Bruckheimer has said a script for a third movie written by Chris Bremner is finished. Have you seen this script?

There is a script. That’s all I’ll say. There have been a few different scripts, actually, but the one thing that has to happen is for all the stars to align. I had seen something awhile ago, and it was solid, but the unsung hero of these movies that doesn’t get mentioned as much is Jon Turtletaub. Those movies really are an extension of his being. He is very smart and funny, and has a buoyancy to him that mirrors the tone of the movies. I think he has to feel really comfortable and feel like he can see the movie before it happens — and it is getting closer to that.

With all of this circulating for a decade and a half now, and your initial skepticism about the series, are you happy you stepped back into Riley Poole’s shoes for this episode? Before he jets off, he gets a mic drop moment, telling Jess that one of her friends might be a traitor, thanks to an off-screen tip from Ben’s mother, Emily (played in the 2007 film by Helen Mirren).

I am thrilled to be able to be involved in any way. I love this guy and this world. I’m just in it for this one episode, and we only shot for one week. But it was this wild experience to step back into it after all these years and have it click right back in. And it was a lot of fun to play off new energy with this cast.

Maybe it was just teasing you for what’s to come with the franchise.

We shall see. Depends on how many people write their Disney Congressmen.

This interview has been edited and condensed.