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FOX has released a new promo for "24: Live Another Day" which sheds more light on the storyline. The video reveals that Jack Bauer tries to stop an attempted assassination of the U.S. president in London, something that may cause a world war. "If an American president is assassinated on foreign soil, you're looking at a world war," the heroic agent tells someone unseen.

Four years after the events in the series finale, Kiefer Sutherland's Bauer is now an exile and is being hunted by a CIA agent. Nevertheless, he is willing to risk his life and freedom to avert yet another global disaster. He attempts to thwart an unthinkable terrorist attack in London that could change the world forever.

Mary Lynn Rajskub returns as Chloe who is now working underground, and William Devane reprises his role as James Heller who is now President of the United States. Benjamin Bratt stars as CIA head Steve Harries, Yvonne Strahovski plays CIA agent Kate Morgan, Giles Matthey is CIA computer tech Jordan Reed, and Gbenga Akinnagbe is cast as a strong and arrogant field operative named Erik Ritter.

"Game of Thrones" alumna Michelle Fairley was recently tapped to tackle a villainous role as Margot, a British national and widow of a notorious terrorist. She replaces Judy Davis who bowed out of the 12-part miniseries due to personal family matters. Stephen Fry also joins the caset in a recurring role.

The "24" revival premieres with a two-hour event Monday, May 5 at 8 P.M. on FOX.