The yet-to-be announced sequel is under development by Infinity Ward, though a swath of those developers left the company in a civil-litigation uprising last year. The team is being assisted by newly minted Activision studio Sledgehammer Games, we're told. We've also heard that Raven Software may be involved.

The Call of Duty series has long alternated between two sets of stories and timelines. The games made by Treyarch have typically been set during the events of World War II, though last year's Call of Duty: Black Ops moved the setting to the Cold War of the 1960s. Starting with 2007's Modern Warfare, Infinity Ward's Call of Duties all took place in a modern day setting.

In the original Modern Warfare, a civil war breaks out in the Russia of 2011. The story continues in Modern Warfare 2, which has a terrorist attack in Russia erroneously linked to the United States. That leads Russian forces to invade the U.S. Some of the missions even feature rolling ground combat in the Washington, D.C. suburbs of Virginia and in the capital itself.

Key to the near ending of Modern Warfare 2, was the detonation of a nuclear missile in the upper atmosphere above the Mid-Atlantic, something that creates an electromagnetic pulse that destroyed all electronic equipment on both sides of the raging war in D.C. Such an event would cripple the area in the short term, essentially removing the ability to use most technology in the region as the country tries to rebuild or bring in support from other parts of the country. It also seems that it could make the story a hard one to follow in a modern day shooter.