With Josh’s life on the line, Eve traverses the dangerous wilderness back to the clearing to save him. Desperate to kickstart a rescue mission, Gavin and Izzy work to prove there are survivors alive inside the sinkhole as government agents track their every move.

With cold weather approaching, Eve, Levi and Ty return to the fort, despite their near-death experience there, hoping to learn 10,000 B.C. survival skills. Gavin's attempts to spare Izzy pain threatens their relationship.

Gavin leads his family toward a new way home, but each step inches everyone closer toward his devastating vision of Eve's death. Levi, ostracized from the others, is given a chance at redemption when an old foe proposes a deal.

As Gavin and Sam search for a secret military base, they're surprised by an old colleague of Gavin's who just may hold the clues to finding Eve. When Ty and Sam try to figure out how to bring their friends home, Ty becomes sidetracked as he confronts his demons from his past.

When a massive fire breaks out, forcing everyone to flee, Sam and Lucas lead the group's fight for survival. Gavin is kidnapped by a woman with a surprising connection to his old life who may hold the answers about Eve that he's been seeking.