When Cal wakes with a life-threatening fever, Grace worries it's a side-effect of his experimental cancer treatment, but Michaela and Ben suspect Cal's condition may be related to a mysterious passenger from Flight 828. As Cal's situation worsens, Ben and Michaela attempt to track down the now-missing passenger.

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.

The Stone Family struggles to unlock their mysterious wave of frightening 828 callings, while the person who may be key to solving them is trapped behind bars. Meanwhile, a shocking and disturbing incident leads Grace to suspect a local mom is in danger.

As a storm rages outside the Stone home and anxieties boil over inside, Olive frantically searches for meaning in a centuries-old text. Meanwhile, Michaela faces unexpected scrutiny at work, and Zeke comes to Saanvi's aid when her lab research takes a dangerous turn.

Ben and Saanvi join forces with Vance in his newest venture to understand Flight 828. Michaela and Zeke adjust to their new home life together, but they pivot to aid a non-passenger with a looming death date of their own.

Ben reunites with a duplicitous foe. Michaela and Zeke's dinner party with Jared and his new girlfriend is halted by a calling that ignites the Stone siblings to save the life of one of their own. Olive's friendship with Levi blossoms but is tested.

Cal tries to understand his scar. A Calling leads Michaela to 828 co-pilot Amuta, who sheds light on what he saw. Ben makes an emotional connection.

An ominous Calling shakes up Michaela and Zeke’s party. Cal and Ben receive devastating news. Michaela, Saanvi and Eagan look for the Omega Sapphire.

As terrifying plagues descend on the detention center, Saanvi scrambles for a solution and Michaela steps up in a crisis. Cal attempts to reach Angelina.

As the Death Date nears, Callings begin to take a toll on Cal. The group sends out a cry for help. A familiar face provides hope in an unexpected place.