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.

Dakota Fanning, Matt Frewer, Emily Bergl, Rei Hance, Joel Gretsch, Adam Kaufman, John Hawkes, Ryan Hurst, Camille Sullivan, Eric Close, James McDaniel, Andy Powers, Chad Morgan, Steve Burton, Julie Ann Emery, Catherine Dent, Jason Gray-Stanford, Desmond Harrington, Brian Markinson, Tina Holmes, Roger Cross, Nathaniel DeVeaux, Emily Holmes, Chad Donella, Willie Garson, Timothy Webber, Max Martini, Anton Yelchin, Gabrielle Rose, Michael Soltis, James Kirk, Tobias Mehler, Ian Tracey, Brenda James, Alonso Oyarzun, Anysha Berthot, Devin Douglas Drewitz, Taylor Reid