"Overwatch." The stolen Black Dragon war drone has spearheaded Cobra's shock assault on Philadelphia — the birthplace of American democracy. Now Cobra Commander unleashes a platoon of deadly urban combat specialists, the Street Vipers, to steal the Constitution itself. Outgunned and outnumbered, the G.I. Joe team fights to keep the heart of the nation out of Cobra Commander's ruthless hands — only to face the ultimate betrayal, when a traitor shows the unsuspecting Joes where his true loyalty lies.