When a massive sinkhole opens in Los Angeles, the Harris family is split in two. Eve and her son are sent to a mysterious primeval world. Gavin discovers that the visions that have plagued him for years might hold the key to bringing them home.

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 the survivors' food supply dwindling, Eve and Ty venture into the forest on a risky hunting expedition. As an unlikely rescue mission comes to fruition, Gavin must put his faith - and the fate of his family - in the hands of an old friend.

The sight of a crashing plane spreads a wave of unexpected hope through the clearing as Eve and the others search for its fallen pilot. Gavin and Izzy seek help from an unlikely source after the government permanently suspends their sinkhole mission.

Eve, Levi and the rest of the search party explore a mysterious fort that raises more questions than answers. With the help of a new ally, Gavin and Izzy embark on a dangerous and unauthorized mission to save their family despite government warnings.

With time running out before their window home closes, the survivors hatch a final escape attempt, but that plan is put into question when they receive a stark warning from Gavin that it will end in disaster, forcing Eve to make an impossible choice.

When a chaotic superstorm hits the clearing, a structural collapse puts Marybeth and Lucas' lives in danger. Still at odds with everyone, Eve desperately tries to make amends by leading the effort to dig them out. Gavin embarks on a journey into his past.

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

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 to saving them. Gavin and Izzy must rely on a stranger if there is any hope to reunite their family.

With news of one last sinkhole opening, Gavin, Izzy and Dr. Nathan race to Seattle to launch a final rescue effort before it's too late. Eve embarks on a perilous journey to send a young boy though a portal in order to save her family.