J. J. Abrams – författare

Agents Sydney Bristow and Marcus Dixon are hot on the trail of a drug lord who has created a mind-control drug so potent that in the wrong hands it could be one of the world's most dangerous bioweapons. Determined to halt production of the substance, the agents go undercover as dealers. Their approach proves to be successful when the drug lord invites them to his estate -- the perfect chance for Sydney to snoop around and find the location of the main lab. But things don't go quite as planned. A government agency interferes with APO's mission; Sydney is forced to ingest a dose of the drug and commanded to turn on her APO counterparts; Dixon is taken hostage; and someone believed to be an ally turns out to be more foe than friend....

Sydney's conscience struggles with her job, which too often asks her to work with criminals she'd much rather put away. She understands the logic -- the small fish versus big fish pragmatism -- but that doesn't make acceptance easier. Someone else is less conflicted and is assassinating APO's shadier contacts. Only the calling card of a black star with the number 13 in its center hints at the culprit. When it becomes clear that a highly trained -- and lethal -- vigilante organization is interfering with APO's missions, Sydney must put aside her empathy and help shut down the mysterious "13 Stars." But after Sydney herself is mistaken for a freelance terror agent, she worries that the mistake is not so far from the truth. And now that she's marked, both her cover and her welfare are in immediate jeopardy.