Black Widow #1 by Mark Waid

A master spy goes rogue, blasting out of a S.H.I.E.L.D. helicarrier with a stolen item and tearing through a city in a relentless, near-silent chase as elite agents close in. Branded a traitor and hunted by former allies, she outwits pursuit at every turn while hints of a shadowy blackmailer leveraging painful secrets from her past reveal that her betrayal may be part of a larger, more dangerous game.