Directors Rachel Grady and Heidi Ewing are practically prescient in their pick of film topics. Their documentaries focus on smaller stories with long-reaching effects.

Their Oscar-nominated doc "Jesus Camp" is about children studying evangelical Christianity, but, years later, it's even more relevant with the advent of the religious right. "12th and Delaware" portrays an intersection in Florida where an abortion clinic sits across the street from a pro-life crisis pregnancy center. Their latest release, "Detropia," is about the city that was once the home of American manufacturing and is now fighting to come back from the edge of bankruptcy.

"Detropia" takes a bird's eye view of the city's economic troubles and what it could mean for America's economy, while also using the stories of lifelong Motor City citizens to illustrate why it's so important to them that this city comes back from the brink. Once a destination for those who wanted a good, solid life and a livable wage, Detroit is now full of homes left empty to be razed and picked apart for scrap metal, and city services have been drastically cut across the board. Nevertheless, there are diehard Detroiters who are fiercely fighting for the city they love.

Ewing and Grady introduce us to a number of Detroit residents, such as blogger/photographer Crystal Starr, who explores and documents the city's abandoned buildings, Tommy Stevens, who owns the Raven Lounge, and George McGregor, the president of United Auto Workers Local 22, who takes us through the more detailed labor woes of the local car manufacturing industry, as well as a personal tour of when its plants were booming.

Change is coming for Detroit, and for America, and how one foreshadows the other is at the heart of "Detropia." We met with Ewing and Grady in the Lower East Side office for Loki Films, their production company, to chat about why Detroit's future matters on a larger scale, gentrification and revisiting subjects.

Heidi Ewing: Well, you just opened with what our biggest challenge was. I mean, trying to make a film about any city is virtually impossible, and a city with the history and the importance and the sort of epic place in American history as Detroit makes it even more challenging. So you could do it in many, many different ways. There really needs to be 10 films on Detroit. We're very, very aware of that. And this is definitely not a complete portrait of Detroit. It's our portrait of Detroit.

But having said that, you do make choices. For example, we didn't do a lot of history. We decided that Detroit has had and deserves its own historical film that looks at Coleman Young and the riots. So, how did we decide what to do, Rachel?

Rachel Grady: In the beginning, we didn't decide. We just explored and explored and explored, and eventually things emerge from your material and things that seem to just be — it's an organic process. Things emerge and you just follow those paths. We did try and include a little bit of everything, so we don't, for instance, really delve that deeply, as Heidi was saying, in the historical. We kiss it with a little bit of archive from the riots and a little bit of archive from back in the day.

HE: [Starr]'s fearless. She'll go anywhere and everywhere. That's her thing. She's amazing.

RG: People are coming from all over the world to do that. It's become a tourist attraction for that… Especially for Westerners from all over the world, the idea of an abandoned skyscraper is mind-boggling. But as a life-long Detroiter and second-generation Detroiter, I think that it's not just that for her, that it's also trying to connect with a past that was boiling over with potential.

HE: And we could have followed tourists into the train station or into the abandoned buildings and some of the new kids, but we wanted to show the Detroiters themselves interact with these spaces. They have opinions about these spaces. They know stories and history of these spaces that their parents told them. So we really were careful that if we were going to film in these locations, we would go with a Detroiter who naturally goes and interacts with the space because Detroiters interact with the so-called blight or with the vacancy and with what was and what could be. We definitely wanted to see it through someone like Crystal's eyes, who was born and raised and has no intention of leaving. And she could, but something keeps her there, and part of it is this mystery of the past. She was kind of the perfect person to go on those explorations with, and I think she adds a different kind of dimension to the movie as well.

Because there's so much actual empty space, is it different than the typical gentrification cycle of a city? How is it viewed? Are these people interlopers? Like, the young artists that you show.

RG: Because the city is so huge and the communities are so spread apart, it hasn't gotten to there yet. There's not enough of them. There's not enough of an overlap. So I think the black community and the people that have been there for a long time — it's funny, the first couple of times we mentioned it to our subjects, they were like, "What are you talking — Really? White folks are living there? Wow!" Maybe now, I don't know, it changes week by week there, month by month. It's a city, it's a dynamic place. But there's no interaction between them.

So it's like it's the cycle of gentrification in other cities, but I think at a little, micro level, it's not like 12 streets, it's like a little pocket here, a little pocket there. They're there. In a way, it's like other towns, but as Rachel mentioned, it seems like there's a lot less overlap between the different Detroits, and that is something that is going to have to be resolved.

It's so interesting to me that your movies are on really ahead of the curve. "Jesus Camp" came out in 2006, and now the evangelical movement is bigger than ever. Of course, "12th and Delaware" is about one of the foremost political topics today, abortion. What do you think 12th and Delaware looks like today, that corner?

HE: Oh, god, it's a s**t show, I'm sure… I was thinking about "12th and Delaware" yesterday and how I really wish we could get it out there again. Because I'll tell you, that corner, the same — maybe worse. Because in an election year, people get pumped up, crazy s**t happens, and you've got — I would say it's probably more heated than it was when we were there.

Do you ever feel like going back and revisiting the stories of the people that you met and talked to, checking up on them?

RG: I do, for my first film, "The Boys of Baraka." I do. We're still in touch with all of them, and it's not that their paths are incredibly surprising. You could have predicted where they are pretty accurately then. But it still would be very compelling, and I think would be able to conjure up conversations and be a study of how important your first 12 years are and how that's it. For most people, that is your path.

HE: I never feel the desire to go back ever and film someone again or do a follow-up. Maybe that will happen one day when it's like, god, I really need to make part 2 or whatever. But for me, these are relationships. That is such a strange dynamic in a relationship between a subject and yourself. It's really hard to describe to anyone. And when you meet someone, and you're starting a film, and you're trying to explain to them the process, they don't understand what's going to happen. You can try to explain, but you're building this interesting dynamic with someone, and that's kind of for life. It's shorthand.

It's a really special dynamic that a documentary film-maker has with her subject. And I think we honor that. I think we recognize it, and we keep in touch with people. We recognize that something happened, something cool, something different.