After The Maze Runner became a sleeper hit, the cast knew they'd be back for films based on the next two novels by John Dashner. First up was The Scorch Trials, which throws the plucky group of teens into various post-apocalyptic locations outside that maze.

The Scorch Trials'The Scorch Trials' is the second chapter in this teen dystopia franchise

The leader of the ensemble is Thomas, played by Dylan O'Brien, who rose to fame on the TV series Teen Wolf. The Scorch Trials has a lot more action than The Maze Runner, and he found it a challenge. "What's funny is on Teen Wolf they'll never get me a stunt double," O'Brien laughs, "because it's a money thing and it's not like I'm ever doing a wolf flip or anything. They'll be like, 'Just fall down the stairs.' On this I have a stunt double, but it's never really anything extreme. It's always something that would work better if I do it, which I think is really important to the spirit of the book. I also love doing stunt stuff and action stuff. But I didn't think it would be more running. This film has me running everywhere."

Watch the trailer for 'The Scorch Trials' here:

He also gets to kiss his two female costars. "Everything I love about this storyline is that it's so unromantic, and that's what makes it so romantic," he says. "There really is no romance going on. There are connections there for the audience to root for, and I think that's stronger without just throwing it in your face."

More: Watch the trailer for 'The Maze Runner'

One of his romantic leads is returning cast member Kaya Scodelario, who plays Teresa and agrees that this film was a lot more physically demanding. "It blew my mind the first week," she laughs. "It's been tough, it's been really, really tough. I'll hold my hands up and say I'm the most unhealthy member of the cast. I do not exercise, I do not live a healthy lifestyle, and I have to start now because, in the first week, we shot in the desert running up sand dunes. But it's nice that we have such a good supportive group. Dylan would high-five me when I actually managed to run fast enough!"

More: Check out photos from 'The Scorch Trials' fan event