Exclusive: ‘G.I. Joe: Retaliation’ trailer shows The Rock, Bruce Willis, and London’s destruction

And London was having such a good year.

The Summer Olympics were a big success, William and Kate are expecting, it seemed like everything was going great for the Brits. But then COBRA agent Zartan, disguised at the President of the United States, zapped Big Ben with a superweapon from outer space and decimated the center of old London town.

At least, that's what happens in the new trailer for "G.I. Joe: Retaliation," the second big-screen adventure based on the beloved action figure line. In this one, Dwayne "The Rock" Johnson joins the cast as Roadblock, the team's Heavy Machine Gunner. He's out in the field with Duke -- once again played by Channing Tatum -- when an airstrike is called in that decimates their crew. Roadblock realizes that the President has been compromised, and sure enough, the White House is soon flying the COBRA flag.

[Photos: 'G.I. Joe: Retaliation' posters and stills]

Needing help, Roadblock and the few remaining members of his team -- Lady Jaye (Adrianne Palicki), Flint (D.J. Cotrona), and Snake Eyes (Ray Park) -- turn to the only man they can trust: General Joe Colton (Bruce Willis). And together, these Real American Heroes face off against the forces of COBRA. Which, of course, means gun fights, armored vehicle attacks, and a ninja battle on the side of a mountain.

After originally being scheduled for release last summer, "G.I. Joe: Retaliation" will finally open in the U.S. on March 29, 2013. It's scheduled to open two days earlier in the U.K., so Londoners better check it out before it's too late.

[Related: Dwayne Johnson in the 'Pain & Gain' poster]