Transcript for Behind the Scenes of 'Captain America: Civil War'
Thank you, ginger. Now big screen battle. "Captain America: Civil war" is the latest in the avengers series and nick watt is taking us behind the scenes on the set with the stars. You know I wouldn't do this if I had any other choice. But he's my friend. So was I. Reporter: It's the avengers but gone wrong. It's "Civil war." Captain America versus ironman. I have a strangely serious investment in the films. Reporter: Who do you mean by that. It won't be entirely predict predict predictable. Characters make choices that surprise you. You seem defensive. The comic books were wonderful pieces of literature. Reporter: And the basis for the film but it will diverge from the source material. I think that marvel likes to keep the fans excited and guessing. Curious, all that stuff. Reporter: Are you a good person or bad person. I think we're all good and bad in this film. You're all good and bad. Because it's a civil war. Downey is playing a much darker version of Tony stark than he's ever played and just crushing it. Sometimes I want to punch you in your perfect teeth. Reporter: Russo says you go to a dark place in this movie. Good. Reporter: There are two teams. Are you on the same team? I can't tell you. That's none of your business. Reporter: Chadwick. I'm on my own side. Marvel newbie Chad wick Bozeman is -- Try calling me that. Reporter: We're on a hot and Muhammad set outside Atlanta. We have cooling systems, literally that like fit underneath their uniform? My dad was a roofer, you know, so I've seen the workman's half of reality, so when I'm out here in a costume and they're liepg, oh, we need you to run in the heat in a costume. Done, so I don't have to get on the roof, let's do it? Can't complain. You're out of your mind. Get to come and play and eat and they feed you -- Free food. Reporter: Which can be a curse or a blessing. I got food poisoning from chicken noodle soup last night. Ugly scene. So sad, it was such good chicken noodle soup. Reporter: One thing he learned off set stay on the straight and narrow. You don't want to do something in your private life that's horrible and have this ruined. Reporter: It's a romance between cap and bucky but with a redonculous special effects. Nick watt, ABC news on the set of "Captain America: Civil war." On the roof. Hey, everyone. I love that idea. I like that. We don't know who is going against who. We'll find out soon, "Captain America: Civil war" out may 6th.
This transcript has been automatically generated and may not be 100% accurate.