The origin story of younger, hungrier, former Green Beret Bryan Mills as he deals with a personal tragedy that shakes his world. As he fights to overcome the incident and exact revenge, Mills is pulled into a career as a deadly CIA operative, a job that awakens his very particular, and very dangerous, set of skills.

The show takes place from 1944 to 2002 and follows the lives of three families: the Crawfords, who seek to cover up the Roswell crash and the existence of aliens; the Keys, who are subject to frequent experimentation by the aliens; and the Clarkes, who sheltered one of the surviving aliens from the crash.