'1917': New trailer shows the horrors of war in this epic single-shot movie

The concept for 1917 is so shockingly simple I’m surprised it’s never been done before: A war movie told in one single continuous 2-hour shot. Of course, the reason it hasn’t been done before is obvious: It’s extremely difficult to pull off, and at a New York Comic-Con panel, director Sam Mendes joined the movie’s cast and crew to discuss the shocking amount of work that went into 1917 before revealing a brand new trailer.

The trailer (above) re-uses much of the footage from the first 1917 teaser released earlier this year, but we also get a closer look at some of the movie’s most harrowing scenes. We also get a look at Andrew Scott (Fleabag, Sherlock) in his role in the star-studded film that mostly focuses on two young, unknown British actors.

1917 tells the story of a pair of soldiers in WWI tasked with delivering a vital message. The Germans had retreated from their entrenched position to a new, heavily fortified position called the Hindenburg Line. The only problem? A British battalion of 1,600 soldiers is headed for the Hindenburg Line with no idea they’re walking into a trap. Our heroes have to race against the clock — and through booby-trapped enemy territory — to deliver the message and save those men.

While the general history here is accurate, the characters are fictional. However, Mendes did reveal that his own grandfather, who fought in WWI, served as the original inspiration for the story.

“I think the first time I understood war was when my grandfather told me his experience of war,” Mendes told the crowd at the NYCC panel. “He told me a story about carrying a message.”

From there, the team behind 1917 poured themselves into research to fill in the blanks. Cinematographer Roger Deakins said he was inspired by an old photo of a group of soldiers, particularly a young man looking into the camera. “He looked so lost.”

Meanwhile, actor Dean-Charles Chapman also took inspiration from his own family history in an unexpected way. After picking up a book of diaries written by WWI soldiers, Chapman discovered that his own great-grandfather fought in the war.

“He was in the cavalry and got shot,” Chapman said. “He laid out in no man’s land for four days before finally being rescued.”

*1917 hits theaters on December 25.