A new trailer for Harry Styles nearly drowning! (If Nolan kills off the former One Direction star, we will never hear the end of it!)

"Dunkirk" tells the real-life story of how civilians rushed in to save 400,000 stranded Allied soldiers during one of the fiercest battles of the war.

In voiceover we hear (we assume) Kenneth Branagh (who plays a grim-faced naval commander) say: "What has happened is a colossal military disaster... we shall go on to the end. We shall never surrender."

We also get good glimpses of "Bridge of Spies" Oscar winner Cillian Murphy as one of the sailors he rescues, who then refuses to go back to the battle lines.

We get much briefer a look at James D'Arcy as an officer who doubts the use of the civilian forces.

Here's the full trailer for the movie, which opens July 21.