Five years into the future in Gareth Edwards' Monsters, an alien invasion has left Central America infected and an American journalist (Scoot McNairy) agrees to escort a tourist (Whitney Able) across the border to safety in the United States. What ensues is a highly improvised post-apocalyptic road trip with hostile creatures and character-focused drama that Edwards shot on location in Guatemala, Mexico, and Texas with a skeleton crew and an indie-movie budget. Monsters is also one of a handful of films that earned a distribution deal after premiering at SXSW – a day after we spoke with McNairy, Magnet Releasing picked up the film.

I spoke with the affable McNairy about his experience filming Monsters, which has been compared to the lo-fi mumblecore movement in dramatic indie film (or, what FEARnet's Scott Weinberg terms "mumblefield" in his review here).  McNairy, best known for his role in the independent dramedy In Search of a Midnight Kiss, also revealed how his real life relationship with co-star Whitney Able led to their involvement in the film and responded to the comparisons to the big-budget monster movie Cloverfield. Read my conversation with McNairy after the jump.

What was your reaction following your SXSW premiere?

I'm floored and blown away with what Gareth did with the resources he had. I'm unbelievably impressed with Vertigo for taking the chance on a movie like this. Last night was the first time I'd seen it; I'd finished the film and all of a sudden I'm up on stage still processing it. But even after being there and shooting the film, it was still a new film to me because there was so much that I didn't see while I was there.

Like the creatures, for example?

The creatures, the special effects, everything. And I don't want to give too much away, but the film is about monsters, but it lends itself to another genre as well. I'll let people make their own decisions on that.

The word after your premiere was pretty positive. Does that validate the unconventional way you folks shot the film?

We haven't read one review, we've heard nothing so far… I'm just happy people are making these kinds of films – quasi low budget, a small crew; I love that atmosphere of working with less people on set, like guerilla crews. I feel like it gives a lot of time to the creative process to unfold and churn, and everybody's a part of how things are going to be done and what's a good idea for this, and I have an idea for that. Whereas on bigger projects you have so many people waiting and there's money involved and time involved; you tell a painter, "I need a painting to be done in an hour," there's no process in it. So I enjoy it; I would love to be doing back to back films with crews of 15 people. 

How did you first get involved with Gareth?

The entire film was improvised, which was a new thing for me and an incredible headache at the same time. Vertigo Films distributed In Search of a Midnight Kiss, so when Gareth had this idea of using an American actor with improvisational skills; Vertigo Films thought, "This guy is great at it, look into him." So Gareth watched Midnight Kiss and flew out to L.A. Whitney, my girlfriend at the time, had done a movie that came out in the U.K. called All the Boys Love Mandy Lane, and they thought it would be a great match. "They're already dating, we want them to have chemistry to be able to improvise…" So it was kind of a nice fit; we talked to Gareth, who stayed with us for about five days on our couch, and every morning we talked and talked. He'd already written out a pretty detailed treatment, so we started talking about characters and what we'd like to bring to it, their dynamic, just hashing it out over the course of a week. He went back to the U.K. to Vertigo and talked with them, and within a month we were a go.

What were the basic story points that Gareth had before you started working together?

He knew he wanted to have an infected zone, and he wanted it to be a road movie and to have two characters who have to get through this area that there's no way to get through. He knew that in that process people would say, "Well why don't they just take the water? So let's eliminate the water." And he knew that he wanted them to get to America and for something to happen in America. So it was pretty well thought out, it was just a matter of how do we tell that story through the dialogue instead of just having two people walking and doing it? And the conflict and the struggle and their relationship… it was a really organic process that was a total hit or miss. It could have just been shit, so I hope and feel that with what we had we did an amazing thing. Once again, we'll let the audience decide if that's the case.

How long was your shoot and how much preparation were you able to do beforehand?

Most films that you get, on my level, you find out two weeks before and it's like, "Alright, you've got to work in two weeks." It gives you limited time for character and back story, which is a necessity for an actor. This film, we had two and a half months to prepare. So I was able to do a massive amount of research on photojournalism, war photography, I developed a back story for my family and where I came from -- which I do on most projects but it's so limited because we have to move so quickly. So we had two months to do our research; I spent two weeks up in Big Sur by myself to isolate myself from my girlfriend and my friends and my house, and just lived in the woods and studied photography. Then we shot for six weeks – we started in Baja, went down there to prep for three days, then flew over to La Paz on the mainland, took a train down to Chihuahua, flew to Mexico City, flew to Cancun, shot a week in Cancun, shot three days in Tulum, got in a car and drove through Belize, shot five days in Guatemala, and then we flew home. They went in cut for six months, called us back and we shot in Costa Rica and shot in Galveston, Texas after Hurricane Ike. It was a total of an eight week shoot.

At that kind of pace, was it particularly hard to be working without a traditional script?

It was a lot of trusting in Gareth, and being willing as an actor to try out new things and being okay with falling flat on your face. Really staying with it and not getting frustrated, just working really hard at it.

Some critics have described Monsters' genre as an amalgamation of mumblecore and horror. Do you find that to be accurate?

It's interesting that you bring that up. Midnight Kiss was thrown into the mumblecore category, but it had a 140-page script that we would cut, and it had a massive amount of improvisation in it. But it had an incredible amount of structure. When it was described as mumblecore I was kind of taken aback, because I didn't think that this was mumblecore. If anything was mumblecore, I think that Monsters – which is a sci-fi film – takes on the genre absolutely. I'm a story guy; when I read a script I'm there more for a story than the camera work or the production value, because if it's a good story it doesn't matter. There was an article about us and Joe Swanberg and they classified it all as mumblecore, so I don't know – classify it as what you want. At the end of the day I think everyone in that category are hard working actors, hard working directors, and hard working screen writers. The Duplass brothers came out of that and they're working on big budget films that are scripted. So I don't know where the mumblecore thing came up, but call it what you want.

Without being too spoilery, what should people expect concerning the horror and sci-fi aspects of Monsters?

I would say just be open to it. It's not what you expect. Monsters is a title that has a subtext; yes, there are monsters in the film and it's called Monsters, but I wouldn't say the film is called Monsters because there are monsters in the film. I'd probably never say what that is, because I know what it is for Whitney, Gareth, myself, and Allan Niblo and James Richardson, the two producers, but I will say this may not refer to the monsters in the film. There are gore elements to it, there's blood, but it's just not what you think. I would say that it's the most realistic, real film in that genre that I've ever seen. It's very, very real.

How would you address any potential comparisons to, say, District 9 or Cloverfield?

This is not me saying this, but something someone said to us was that this kind of looked like what Cloverfield was going for. It's a very realistic film but it was still a studio film. I think this film that we made couldn't have been made by a studio. But that's only going based on the shoot; I'd much rather the audience make their own assumptions and their own opinions.

Tell us about another horror film you did, Wreckage.

Wreckage is a film I did with a good friend of mine, Aaron Paul. John Asher directed it, and we shot it, me and Cameron Richardson and Mike Erwin. We shot that four years ago, and like a lot of movies in Hollywood it went through editing hell, and politics and I don't know where it's at now.

How did you come to this recent run of indie horror films?

I don't know, horror films have never really been my thing. I'm much more into dramas and comedies, yet as an actor I'm open to all kinds of genres. Wreckage came about because Aaron was working on the project and he pitched me to the director, and I'd really been wanting to work with Aaron – I think he's a f***ing fantastic actor. It had a little bit bigger budget than Monsters, but it was definitely an independent horror film. And that's what we set out to do, to make a horror film that had all the key elements of what makes a horror film work. We shot the whole thing and no one's seen it, but I'm not quite clear on what's happening with it.