An armored car driver tries to elude a gang of thieves while a flood ravages the countryside.

Season three reveals an origin story set centuries earlier, while continuing the saga of a dystopian society of 10,000 people living underground under mysterious circumstances. In the present, Juliette Nichols survives her forced "cleaning" but returns with memory loss as the silo recovers from rebellion and faces a dangerous new threat. Meanwhile, in the "Before Times," journalist Helen Drew and Congressman Daniel Keene uncover a conspiracy that pulls them into a chain of events with catastrophic, irreversible consequences.

When rogue stealth-fighter pilot Vic Deakins deliberately drops off the radar while on maneuvers, the Air Force ends up with two stolen nuclear warheads — and Deakins's co-pilot, Riley Hale, is the military's only hope for getting them back. Traversing the deserted canyons of Utah, Hale teams with park ranger Terry Carmichael to put Deakins back in his box.