Flashbacks reveal how Grace, Olive and Jared coped with the loss of their loved ones after the disappearance of Flight 828; Ben tries to escape the voice in his mind by going on an adventure with Cal; Michaela struggles with her feelings for Jared.

Michaela's mystifying, next-level calling launches her on a mission that brings her relationship with Jared to a head. Determined to protect his family, Ben explores an alternate meaning to Michaela's calling that leads him to a new alliance and a powerful new adversary. Cal's struggle with Ben's absence from home forces the Stones into an agonizing confrontation that could alter the family's fabric forever.

As the passengers adjust to a frustrating new reality, Ben and Michaela seize an opportunity to solve a Calling, with the Registry in hot pursuit.