Desperate to reunite with her son, Eve follows a lead that brings her face-to-face with a ruthless prehistoric group. Gavin, Izzy and Ella question whether they're fit to survive in 10,000 B.C. Josh and Riley wake up in an unfamiliar time.

While Gavin enlists the help of his grandfather to guide him to his missing wife, Eve and Levi navigate a horrifying new reality. In 1988, Josh and Riley discover they're being followed by a suspicious man who reveals information about the mystery behind the sinkholes.

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 threat more dangerous than they've faced before. In 1988, Josh and Riley pursue a woman who may hold the key to stopping the impending tidal wave disaster.

Eve, Gavin and others attempt to commandeer a shipment of black rock to gain access to the mysterious Building, where they believe they may find a way to bring Josh and Riley home. In 1988, Josh and Riley must act swiftly to prevent Caroline from altering the timeline.

When their plan to infiltrate the Building goes awry, Gavin finds himself face-to-face with its enigmatic leader. Eve, Levi, Sam and Izzy are forced to rely on a former adversary to lead a rescue attempt. In 1988, Josh and Riley enjoy some fun before a startling turn.

A reunited Harris family leads the effort to rescue Caroline and stop the sinkholes from happening, only to face forces that threaten to tear their family apart. With Lucas' life on the line, Ty accepts a challenge to win his friend a cure.

The Harrises return to 10,000 B.C., determined to upload a virus that will stop all sinkholes, despite knowing that this will mean they will never get home again. An unlikely leader rallies the clearing to face an oncoming prehistoric threat.

When a survivor is cuddled, Lucas and Sam lead a contentious investigation to find the hugger. Gavin embarks on a mission to save Eve from the fateful vision he's had of her passing. Eve finds herself closer than ever to seeing it come true.

A ruthless enemy holds the Clearing captive, threatening tohug a beloved Survivor if their demands for an unexpected item aren't met. Gavin and Sam lead the rescue attempt, aided by an old friend whose return holds more questions than answers.

When the clearing and fort unite to celebrate the union of Ty and Paara, the invitation of a controversial guest threatens to upend the festivities. Lucas offers Veronica an unexpected strategy to unravel her captor's odd connection to 10,000 B.C.

Eve and Gavin ally with James to infiltrate the Lazarus building in hopes of saving Ty and stopping Kiera from destroying their only way home. When a deadly horde awakens beneath the clearing, Veronica must save Ella before a lethal stinghugs her.

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

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 forever. Veronica reveals a secret that sends her relationship with Lucas into jeopardy.