With news of one last sinkhole opening, Gavin, Izzy and Dr. Nathan race to launch a final rescue effort before it's too late; Eve embarks on a perilous journey to send a young boy through a portal in order to save her family.
When a stunning revelation puts Josh and Izzy's lives on the line, the survivors desperately search for the young boy who holds the key. Gavin and Izzy must rely on a stranger if there is any hope to reunite their family.
The sight of a crashing plane spreads a wave of unexpected hope as the survivors search for its fallen pilot. Gavin and Izzy seek help from an unlikely source after the government permanently suspends their mission.
With cold weather approaching, Eve, Levi and Ty return to the fort, despite their near-death experience, hoping to learn 10,000 B.C. survival skills. Gavin's attempts to spare Izzy pain threatens their relationship.
When their plan to infiltrate the building goes awry, Gavin finds himself face-to-face with its enigmatic leader. Josh and Riley enjoy some fun before a startling turn.
Celebrations on the union of Ty and Paara, until a controversial guest threatens to upend it. Lucas offers Veronica an unexpected strategy to unravel her captor's odd connection to 10,000 B.C.
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.
After an emotional reunion, Gavin and Eve attempt a daring escape from their unforgiving captors. Lucas leads a dangerous mission to the fort to reclaim the resources his friends so desperately need.
When a fog falls over the Clearing, Eve leads a defense against a group of invaders, only to encounter a more dangerous threat. Josh and Riley pursue a woman who may hold the key to stopping the impending tidal wave disaster.
With Gavin on the verge of dying, Eve and her family make a desperate attempt to set things right - even as an unexpected twist threatens to tear them apart. Veronica reveals a secret that sends her relationship with Lucas into jeopardy.
