New 'Oppenheimer' trailer, starring Cillian Murphy, Matt Damon and more, out now

A tense new trailer for Christopher Nolan's star-studded "Oppenheimer" just debuted, showing the United States in a race against time.

"This is a national emergency," frequent Nolan player Cillian Murphy says as J. Robert Oppenheimer, the father of the atomic bomb. "We're in a race against the Nazis. And I know what it means if the Nazis have a bomb."

The film, based on the 2005 Pulitzer-winning book "American Prometheus: The Triumph and Tragedy of J. Robert Oppenheimer" by Kai Bird and Martin J. Sherwin, shows Oppenheimer lobbying Matt Damon as Leslie Richard Groves Jr., a United States Army Corps of Engineers officer who directed the Manhattan Project, which developed the atomic bomb.

"We've got one hope," Oppenheimer says. "All America's industrial might and scientific innovation connected here. A secret laboratory. Keep everyone there until it's done."

To that end, they built a series of towns in "the middle of nowhere." Experts in various scientific and military disciplines are recruited and moved in with their families -- otherwise, they couldn't work around the clock, Oppenheimer reasons.

"Are we saying there's a chance that when we push that button, we destroy the world?" Groves asks, to which Oppenheimer responds, "The chances are near zero."

"Near zero?" Groves asks, incredulous.

"What do you want from theory alone?" Oppenheimer replies.

"Zero would be nice," Groves says.

As the tension ratchets up, Oppenheimer pledges, "Our work here will ensure peace mankind has never seen."

The trailer closes with Kenneth Branagh's character telling Oppenheimer, "You are the man who gave them the power to destroy themselves. And the world is not prepared."

The film also stars Gary Oldman as President Harry Truman, Emily Blunt as Oppenheimer's wife Kitty Oppenheimer, Rami Malek as a scientist, Robert Downey Jr. as former Commerce Secretary Lewis Strauss, Jack Quaid as physicist Richard Feynman, Florence Pugh as Jean Tatlock, and Matthew Modine as Vannevar Bush.

"Oppenheimer" debuts in theaters July 21.