20th Century Fox
July 23, 2015 2:15 PM EDT

The mood is cheery on the set of Paper Towns in Charlotte, North Carolina, this past December. It happens to be star Nat Wolff’s birthday, and he’ll soon be treating the entire cast and crew to ice cream to celebrate. In between takes, Wolff and four other actors are belting out Taylor Swift’s “Blank Space” inside a van surrounded by so many green screens and LED monitors that some folks joke that it looks like they’re filming an action movie instead of a teen comedy-drama. (Indeed, the technology surrounding the van to make the movie’s pivotal road trip scenes look realistic was previously used on Gravity.) Spending several hours in a stationary vehicle doesn’t sound like the most glamorous job in in the business, but with just a few days left before production wraps, the cast is savoring its time together. “I don’t know if you can feel it on set, but something about the energy of everyone putting their heart all into one thing—it’s contagious,” says actress Halston Stage.

Those aren’t the only reasons spirits are high. The last time one of John Green’s bestselling young-adult books became a movie, 2014’s The Fault in Our Stars, its story of two teens falling in love after meeting in a cancer support group became one of saddest movie-going experiences of the year—and at times cast a morose shadow over the production. Paper Towns, out July 24, grapples with less serious subject matter, and the difference is palpable on set. “The vibe is way lighter since nobody’s dying,” Green says.

The movie, out July 24, follows high-school senior Quentin (Wolff) as he tracks down his neighbor and longtime crush Margo (Cara Delevingne), who goes missing after she recruits him for a night of vengeful mischief against their classmates. TIME spoke to Delevingne about how she’s making the jump from modeling to acting, but that’s not all we gleaned from visiting the set. Below are some of the highlights from our two-day visit:

Green is really good at giving presents. As production winds down on Paper Towns in mid-December, Green has started giving the cast and crew some wrap gifts: maps that feature paper towns, the fictional cities cartographers create as copyright traps. He first learned about them on a college road trip, when he passed through what was supposed to be Holen, South Dakota, and found little more than fields. The paper town featured in the novel, Agloe, New York, has also become a minor tourist attraction for book nerds, who leave notebooks and mementos; someone even made an official-looking welcome sign that Green excitedly shows off on his phone.

“What’s sort of metafictional about this whole experience for me is I wrote this novel about how the way that we imagine the world shapes the world that we end up living,” Green says. “And then I have this incredibly surreal experience of having all of these things that I’d imagined become visible.”

There are still black Santas scattered around set in the final days. Fans of the book will remember that the parents of Quentin’s friend Radar (played by Justice Smith) are trying to amass the largest collection of black Santas in the world, much to his embarrassment. “I told [executive producer] Isaac [Klausner] when it became clear that this movie was going to get made, ‘You should spend the entire prop budget on black Santas,” Green says. “Every dollar you spend on black Santas will be money well spent.”

Paper Towns gets a helping hand from Homeland. Much of the Showtime drama has been filmed in Charlotte, which makes a convincing D.C.-area substitute, and some of Homeland’s sets have even been recycled for the movie. If you’re wondering whatever happened to Saul’s house, head to a theater near you this Friday.

John Green still doesn’t know what an author does on the set of his book adaptation. He’s an executive producer this time, but Green says not to put too much stock in his title or the fact that he had a trailer. “I don’t think that means anything,” he says. “Seriously. What do executive producers do?” In reality, Green’s role is something like one-third consultant, one-third archivist and one-third cheerleader. “Most of my job is to be excited,” he says, and the cast agrees. “He’s like the dad who’s always about to cry,” says Jaz Sinclair, who plays Angela, one of Quentin’s classmates. “He’s so excited and encouraging. It’s special for him to see his story brought to life.”

Studios are also seeing the benefit of having an author like Green hang around for most of the filming, as his social media postings don’t just document life on the set, they get a lot of fans excited about a movie they haven’t seen a second of footage from. “[My involvement] is less unusual than it used to be because of Twitter,” Green says. “More movie studios want to include authors because they want to have access to those author’s fans, and more authors now have direct relationships with their readers than they did 10 or 20 years ago.”

Green isn’t interested in screenwriting. Though Gillian Flynn (Gone Girl) and Jonathan Tropper (This Is Where I Leave You) have recently joined the small club of authors who adapt their own books for films—Rainbow Rowell is also doing the same with her 2013 young-adult hit Eleanor & Park—Green won’t be doing the same. He already tried it with Paper Towns several years ago and calls the result “awful.” “I worked on it ceaselessly for six months, and I think we got further and further away from a good movie over the course of those six months,” he says. “I know what I suck at. Obviously Gillian Flynn is an amazing screenwriter. Rainbow’s a good friend of mine and I have every confidence that that screenplay is going to be awesome. I just happen to be a terrible screenwriter.”

Green is big on literary references. In addition to talking about Walt Whitman’s “Song of Myself,” which comes up in the Paper Towns novel, he also shouts out Philip Roth’s The Human Stain, David Foster Wallace and Moby Dick.

He’s still coming to terms with his post-Fault celebrity. Green is on television a lot more, which he doesn’t personally like but endures to help promote the movies drawn from his books. Fans come to his home and ring the doorbell hoping to meet him, which he dislikes as the father of two young children, though he takes some of the blame for not drawing clearer boundaries between what he shares online and his personal life offline. Green has also hard a time with the attention and scrutiny his tweets, blog posts and YouTube videos attract.

“What really changed for me is that I’d always felt very safe in these [online] spaces, and I never checked my remarks or felt the need to be self conscious,” Green says. “[Now] I could say something, and it ends up in Entertainment Weekly. Not only that, but I could say something and then people who are way outside of it interpret it or read it less graciously. Some of that may be helpful because it makes makes me think, ‘Okay, I need to reevaluate my thinking about this stuff,’ but some of it is just terrible and hateful and awful. While it’s certainly a very first world problem, I do feel bullied at times.”

Director Jake Schreier wears a suit to set every day. “He is a control freak, but he is so passionate and talented,” says Wolff, who describes Schreier as typically “running from set to set and drinking eight Red Bulls.” Paper Towns is Schreier’s second feature film after 2012’s Robot & Frank, which Klausner describes as “a moving drama about Alzheimer’s, an incredibly fun buddy comedy, a heist caper movie [and] a science-fiction film.” That made Schreier a good match for Paper Towns’ challenging mix of teen comedy, romance and mystery. “[Robot & Frank] was so many things and yet it never felt like it wasn’t also just entirely and fully itself,” Klausner says. “There are not many directors who are able to pull that off.”

John Green books are the new John Hughes movies. At least according to producer Wyck Godfrey, who knows a thing or two about what teens like, having produced the Twilight series and The Fault in Our Stars prior to Paper Towns. “I would watch a John Hughes movie and [feel] like the dialogue was crisper and sharper than I actually was, and yet it was close enough that I felt I could be if I tried to be,” he says. “John’s characters speak the same way. There’s a heightened sense of humor and cleverness to them that makes you want to be them. That’s what those ‘80s high school films were for me and what a good high school film is. It’s aspirational.”

The John Hughes comparison is apt in other ways, Godfrey continues: “The idea of being able to do a series of his books and start to bring in the same actors in the way John Hughes did with his actors, you start to feel like you’re part of a club you want to be in. Nat’s in this one, you’ll figure out who you can bring back for the next one—it starts to feel a little bit like a family.” Godfrey’s production company, Temple Hill Entertainment, is attached to the next John Green adaptation, Looking For Alaska, which will be directed by Rebecca Thomas and written by returning The Fault in Our Stars and Paper Towns screenwriters Scott Neustadter and Michael H. Weber. When I ask Wolff if he’d consider a role in the film, Wolff says, “I don’t know yet. That’d be cool. I’d love to be apart of anything with John.”

Producers had been eyeing Wolff for the role of Quentin before The Fault in Our Stars finished filming. “Toward the end of shooting, Isaac came up to me and said, ‘You should read this other John Green book,’” says Wolff, who calls Paper Towns his favorite Green novel. “He didn’t say anything about me being in the movie, but I had a sneaking suspicion.” Months later, when Wyck Godfrey called to offer him the role, Wolff said yes before Godfrey could even finish his sentence. “I hadn’t seen The Fault in Our Stars yet, so I thought, ‘I guess I’m good in The Fault in Our Stars!’”

Wolff’s casting helped convince others to get on board with the project, too. Neustadter and Weber told Wolff he was one of the main reasons they agreed to write the Paper Towns screenplay, and Green also cites Wolff as a selling point for his involvement. “When it was the same screenwriters and the same producers and the same studio executives and Nat—Nat’s a big part of it for me—I couldn’t say no,” Green says. “I couldn’t say no to hanging out with Nat Wolff again.”

Wolff is unfazed by his new leading-man status. The attention is probably nothing compared to the fame of his youth, anyway. “I was on a [Nickelodeon] show The Naked Brothers Band and couldn’t leave my house without getting mobbed and recognized,” he says. “It was kind of cool and kind of weird, then it went away. Now it’s started happening again. I just realized that it is sort of transient and unimportant, but nice. It’s nice that people want to see the things that I am in and that they want to talk to me, but that’s not the thing to be focused on.”

It was Schreier’s idea to have the cast live together in the same apartment building. “I like the idea of forming a compound somewhere and staying in it, especially in a movie that’s about friendship and trying to form these bonds,” Schreier says. The actors ate dinner together, watched movies together, constantly hung out in each others’ apartments and played numerous rounds of cornhole in Charlotte. Wolff says it’s rare to find that kind of chemistry: “With every movie that I’ve ever been apart of, they always say in all the interviews, ‘We got along so well and went to dinner every night,’ and 95 percent of the time it’s not true. It either was okay or they didn’t like each other and were covering. [With Paper Towns], it’s honestly true. It’s been like a family since we got here.”

They also almost got kicked out of that apartment. A light outside of Green’s apartment kept the author from sleeping, so Wolff says he and some of his co-stars got ahold of a BB gun and tried to shoot the light out. They weren’t successful, and apartment managers weren’t thrilled when they saw the actors using what looked like a real gun in security-camera footage. Neighbors also made frequent noise complaints, and at the time of our interview, Wolff says they all had one strike left. “It makes us sound like we are wild partiers,” Wolff says. “I have been on those sets where kids are getting drunk all the time time, and it wasn’t like that. It was strangely innocent—three guys wrestling, playing video games all night, doing karaoke, singing loud, doing dumb stuff.”

John Green calls the movie version of the Paper Towns gas station scene “iconic.” Shooting the scene, which also features (spoiler alert!) a crowd-pleasing cameo, was a life-long dream for some of the actors.I’ve always fantasized about going into a grocery store or a country club or something like, ‘I just want to smash everything and knock everything on the ground.’ I actually got to do it on this movie,” Wolff says. When reminded that he already got to wreak havoc and smash trophies in The Fault in Our Stars, he jokes, “John lets me break things, which is what I look for in a script. If I don’t have enough things to break, I turn it down.”

Write to Nolan Feeney at nolan.feeney@time.com.

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