Taking place at the same time as Skyline, Mark Corley, a Los Angeles police detective, helps his estranged son, Trent, out of jail just as an alien invasion begins. Much of the city's population is taken up into various spaceships by a blue light.

Mark leads a group of surviving humans through underground subway tunnels to escape, though most of the humans are killed or abducted. The survivors, Mark, Trent, transit operator Audrey, and homeless man "Sarge" (who is immune to the blue light due to his blindness), escape to the marina following the city's nuclear destruction, only to be abducted into the alien flagship.