Author Stephen King and director Francis Lawrence are both known for deftly handling tales involving kids put through hell with no guarantee they’ll survive. Think the Losers’ Club in It for King and every young person to appear in a Hunger Games movie for Lawrence. So to combine their talents on The Long Walk, based on King’s 1979 dystopian novel, feels rather ideal—not to mention nightmarish, as the film’s brutal first trailer suggested.

At San Diego Comic-Con, fans got a deeper look into the movie with stars David Jonsson, Tut Nyuot, Garrett Wareing, and Mark Hamill, as well as producer Roy Lee and screenwriter JT Mollner. That started off with a brand new trailer, which amps up the dread of the first, and gives us a bit more of Mark Hamill’s chilling performance as the Major, the military leader who watches over the young men participating in the Long Walk… and acts as their angel of death as they’re brutally picked off, one by one.

The rest of the cast includes Cooper Hoffman, Judy Greer, Ben Wang, and Charlie Plummer.

Here’s the plot description, as chillingly simple as it gets: “Set in a dystopian alternative version of the United States ruled by a totalitarian regime, the story follows 50 young men who sign up for the Long Walk, where they walk at a pace of three miles per hour until contestants are eliminated one by one and only one winner is left.” It hits theaters September 12.

Want more io9 news? Check out when to expect the latest Marvel, Star Wars, and Star Trek releases, what’s next for the DC Universe on film and TV, and everything you need to know about the future of Doctor Who.