The brutality of war is on full display in the first trailer for "1917" from director Sam Mendes.

The movie, which features a star-studded cast of just about every acclaimed British actor around, centers on on two young British soldiers on a single day at the height of WWI.

The two soldiers, Schofield (George MacKay) and Blake (Dean-Charles Chapman), are given a seemingly impossible mission. In a race against time, they must cross enemy territory and deliver a message that will stop a deadly attack on hundreds of soldiers—Blake’s own brother among them.

Benedict Cumberbatch, Colin Firth, Mark Strong, Richard Madden and Andrew Scott round out the cast.

This is Mendes' first film since directing 2015's James Bond movie "Spectre." He is reuniting with legendary cinematographer Roger Deakins; the pair previously worked together on "Skyfall," "Jarhead," and "Revolutionary Road."

"1917" opens in limited release December 25 and in wide release January 10.